COOH H———OH 2 . (a) HO———H and its enantiomer-a case of syn addition. Mixture is optically inactive (racemic). COOH COOH COOH H———OH H———OH (b) H———OH meso form by anti addition. (c) HO———H and its enantiomer (racemic) by anti additon. COOH COOH COOH H———OH (d) H———OH meso by syn addition. COOH 4 . A is obtained by syn addition B is also obtained by syn addition CH3 CH3 HH A : C=C B : CH3–C–C–CH3 H cis H D D meso C is obtained by anti addition D is mixture of d-and l-(recemic mixture) H CH3 HD C : C=C CH3–C–C–CH3 D : DH CH3 H d- and - (racemic) E is obtained by syn addition H Br E : as A CH3–C–C–CH3 Addition of Br2 is anti F: Br H H : as F CH3 Br G : C=C Br CH3 trans n–BuCCMe 5. n-BuC–C–H Li Lindlar's catalyst n-BuC–C–H NH3 H2 H CH3 CH3 H3C B-cis H HO———H A-trans (by syn additon) (by anti additon) H———OH n-Bu (C) and its enantiomer (racemic) 6. ; C2H5 C2H5 ; HOOC COOH ; AB CD
10. A , A or A 3 H2 H3CCHCH2CH3 12 CH3 This shows that each of A1, A2 and A3 have same C-chain; only position of (C=C) is to be decided. A1, A2 oxymercuration 3º alcohol demercuration CH3 CH2 C | hence A and A have =C or groupings. 12 CH3 A2 and A3 hydroboration oxidation 1º alcohol This indicates presence of (CH2=) grouping at the terminal. Hence, A1 is CH3C=CHCH3 A2 is CH3CH2C=CH2 A3 is CH3CHCH=CH2 CH3 CH3 CH3 OH A1 or A2 oxymercuration CH3CCH2CH3 3° alcohol (X) demercuration CH3 A hydroboration CH3CH2CHCH2OH 1º alcohol (Y) 2 oxidation CH3 1º alcohol (Z) A hydroboration CH3CHCH2CH2OH 3 oxidation CH3 Y and Z are different 1º alcohols.
EXERCISE - 05 [A] JEE-[MAINS] : PREVIOUS YEAR QUESTIONS 1 . Which of these will not react with acetylene - [AIEEE-2002] (A) NaOH (B) ammonical AgNO (C) Na (D) HCl 3 2 . What is the product formed when acetylene reacts with hypochlorous acid - [AIEEE-2002] (A) CH COCl (B) ClCH CHO (C) Cl CHCHO (D) ClCH COOH 3 2 2 2 [AIEEE-2003] 3 . 1–Butene may be converted to butane by reaction with - (A) Pd/H (B) Zn - HCl (C) Sn - HCl (D) Zn - Hg/HCl 2 4 . On mixing a certain alkane with chlorine and irradiating it with ultraviolet light, it forms only one monochloroalkane. This alkane could be - [AIEEE-2003] (A) neopentane (B) propane (C) pentane (D) isopentane 5 . Which one of the following is reduced with Zn-Hg/HCl to give the corresponding hydrocarbon (A) Butan-2-one (B) Acetic acid [AIEEE-2004] (C) Acetamide (D) Ethyl acetate 6 . Which one of the following has the minimum boiling point : [AIEEE-2004] (A) isobutane (B) 1–butyne (C) 1–butene (D) n–butane 7 . 2-Methylbutane on reacting with bromine in the presence of sunlight gives mainly [AIEEE-2005] (A) 2–bromo-2–methylbutane (B) 1–bromo-2–methylbutane (C) 1–bromo-3–methylbutane (D) 2–bromo-3–methylbutane 8 . Alkyl halides react with dialkyl copper reagent to give [AIEEE-2005] (A) alkyl copper halides (B) alkenes (C) alkenyl halides (D) alkanes 9 . Reaction of one molecule of HBr with one molecule of 1,3–butadiene at 40°C gives predominantly (A) 1–bromo–2–butene under thermodynamically controlled conditions [AIEEE-2005] (B) 3–bromobutene under kinetically controlled conditions (C) 1–bromo–2–butene under kinetically controlled conditions (D) 3–bromobutene under thermodynamically controlled conditions 1 0 . Acid catalyzed hydration of alkenes except ethene leads to the formation of [AIEEE-2005] (A) secondary or tertiary alcohol (B) primary alcohol (C) mixture of secondary and tertiary alcohols (D) mixture of primary and secondary alcohols 1 1 . Elimination of bromine from 2–bromobutane results in the formation of [AIEEE-2005] (A) predominantly 2–butene (B) equimolar mixture of 1 and 2–butene (C) predominantly 2–butyne (D) predominantly 1–butene Me 12. Me OH N Et n Bu The alkene formed as a major product in the above elimination reaction is- [AIEEE-2006] (A) Me (B) CH2=CH2 Me Me (C) (D) 1 3 . Reaction of trans-2-phenyl-1-bromocyclo pentane on reaction with alcoholic KOH produces- (A) 4-phenyl cyclopentene(B) 2-phenyl cyclopentene [AIEEE-2006] (C) 1-phenyl cyclopentene(D) 3-phenyl cyclopentene 1 4 . Phenyl magnesium bromide reacts with methanol to give- [AIEEE-2006] (A) A mixture of anisole and Mg(OH)Br (B) A mixture of benzene and Mg(OMe)Br (C) A mixture of toluene and Mg(OH)Br (D) A mixture of phenol and Mg(Me)Br
1 5 . Which of the following reactions will yield, 2, 2-dibromopropane [AIEEE-2007] (A) CH3—C CH + 2HBr (B) CH3CH CHBr + HBr (C) CH CH + 2HBr (D) CH3 — CH CH2 + HBr 1 6 . In the following sequence of reactions, the alkene affords the compound ‘B’ :- [AIEEE-2008] CH CH=CHCH O3 A HZ2nO B. 33 The compound B is (A) CH CH CHO (B) CH COCH (C) CH CH COCH (D) CH CHO 32 33 32 3 3 [AIEEE-2008] 1 7 . The hydrocarbon which can react with sodium in liquid ammonia is (A) CH3CH2CH2C CCH2CH2CH3 (B) CH3CH2C CH (C) CH CH=CHCH (D) CH C HC CCH CH 33 2 23 3 18. The treatment of CH MgX with CH C C–H produces [AIEEE-2008] 3 3 (A) CH3–CH=CH2 (B) CH3C C–CH3 HH (D) CH4 || (C) CH3—C=C—CH3 1 9 . The main product of the following reaction is [AIEEE-2010] C6H5CH2CH(OH)CH(CH3)2 Conc. H2SO4 ? H5C6CH2CH2 C = CH2 H5C6 C= C H (A) CH(CH3)2 (B) H3C H C6H5CH2 C= C CH3 C6H5 C= C CH(CH3)2 (C) CH3 H (D) H H 2 0 . One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is :- [AIEEE-2010] (A) ethene (B) propene (C) 1-butene (D) 2-butene 2 1 . Ozonolysis of an organic compound gives formaldehyde as one of the products. This confirms the presence of :- [AIEEE-2011] (A) an isopropyl group (B) an acetylenic triple bond (C) two ethylenic double bonds (D) a vinyl group 2 2 . Ozonolysis of an organic compound 'A' produces acetone and propionaldehyde in equimolar mixture. Identify 'A' from the following compounds :- [AIEEE-2011] (A) 2 - Methyl - 1- pentene (B) 1 - Pentene (C) 2 - Pentene (D) 2 - Methyl - 2 - pentene 2 3 . 2–Hexyne gives trans –2–Hexene on treatment with :- [AIEEE-2012] (A) Li AlH4 (B) Pt/H2 (C) Li/NH3 (D) Pd/BaSO4
2 4 . In the given transformation, which of the following is the most appropriate reagent ? [AIEEE-2012] CH=CHCOCH3 CH=CHCH2CH3 Re agent HO HO (A) NaBH4 (B) NH2 NH2, OH (C) Zn – Hg / HCl (D) Na, Liq.NH3 JEE-[MAIN] : PREVIOUS YEAR QUESTIONS ANSWER KEY EXERCISE -5[A] Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans 1 3 1 1 1 1 1 4 1 1 1 2 4 2 1 Que. 16 17 18 19 20 21 22 23 24 Ans 4 2 4 2 4 4 4 3 2
EXERCISE - 05 [B] JEE-[ADVANCED] : PREVIOUS YEAR QUESTIONS 1 . Alcoholic solution of KOH is a specific reagent for - [IIT-90] (A) Dehydration (B) Dehydrogenation (C) Dehydro halogenation (D) Dehalogenation 2 . Of the following, unsaturated hydrocarbons are - [IIT-90] (A) Ethyne (B) Cyclohexane (C) n-propane (D) Ethane 3 . 1–chlorobutane on reaction with alcoholic potash gives [IIT-91] (A) 1–butene (B) 1–butanol (C) 2–butene (D) 2–butanol 4 . The hybridisation of carbon atoms in C–C single bond of HC C – CH=CH2 [IIT-93] (A) sp3–sp3 (B) sp2–sp3 (C) sp–sp2 (D) sp2–sp2 5 . The product (s) obtained via oxymercutation (HgSO4 + H2SO4) of 1–butyne would be - [IIT-92] (A) CH3 CH2 C– CH3 (B) CH3–CH2–CH2–CHO || O (C) CH3–CH2–CHO–HCHO (D) CH3–CH2–COOH+HCOOH 6 . Which is the decreasing order of strength of bases : [IIT-93] OH–, NH , HC C– and CH3– CH 2 2 (A) CH3– CH > NH > HC C– > OH– (B) HC C– > CH3– CH > NH > OH– 2 2 2 2 (C) OH– > NH > HC C– > CH3– CH (D) NH > HC C– > OH– > CH3– CH 2 2 2 2 7 . The chief reaction product of reaction between n-butane and bromine at 130º C is - [IIT-95] (A) CH3CH2CH2CH2Br (B) CH3CH2CHBr CH3 (C) CH3–CHCH2Br (D) CH3–C–Br2 CH3 CH3 8 . When cyclohexane is poured on water, it floats, because - [IIT-97] (A) Cyclohexane is in 'boat' form (B) Cyclohexane is in 'chair' form (C) Cyclohexane is in 'crown' form (D) Cyclohexane is less dense than water 9 . (CH3)3 CMgCl on reaction with D2O produces [IIT-97] (A) (CH3)3CD (B) (CH3)3OD (C) (CD3)3CD (D) (CD3)3OD 1 0 . When [IIT-97] reacts with Ph3 P C HR , the product is - O (A) (B) (C) (D) OH CHR CH2R 1 1 . The intermediate during the addition of HCl to propene in the presence of peroxide is : [IIT-97] (A) CH3 C HCH2Cl (B) CH3 C HCH3 (C) CH3CH2 C H2 (D) CH3CH2 C H2
1 2 . Read the following statement and explanation and answer as per the option given below : [IIT-98] Assertion : Addition of Br2 to 1–butene gives two optical isomers. Reason : The product contains one asymmetric carbon. (A) If both assertion and reason are correct, and reason is the correct explanation of the assertion (B) If both assertion and reason are correct, but reason is not correct explanation of the assertion (C) If assertion is correct but reason is incorrect (D) If assertion is incorrect but reason is correct 1 3 . The reaction of CH3CH=CH OH with HBr gives - [IIT-98] (A) CH3CHBrCH2 OH (B) CH3CH2CHBr OH (C) CH3CHBrCH2 Br (D) CH3CH2CHBr Br 1 4 . In the compound CH2=CH–CH2–CCH, the C2–C3 bon is of the type [IIT-99] [IIT-99] (A) sp–sp2 (B) sp2–sp3 (C) sp–sp3 (D) sp3–sp3 1 5 . The product obtained via oxymecuration (HgSO4 + H2SO4) of 1–Butyne would give – O (B) CH3CH2CH2–CHO || (A) CH 3CH 2 C CH 3 (C) CH3CH2CHO + HCHO (D) CH3CH2COOH + HCOOH 1 6 . Read the following statement and explanation and answer as per the option given below : [IIT-2000] Assertion : 1–Butene on reaction with HBr in the presence of a peroxide produces 1–bromobutane. Reason : It involves the formation of a primary radical. (A) If both assertion and reason are correct, and reason is the correct explanation of the assertion (B) If both assertion and reason are correct, but reason is not correct explanation of the assertion (C) If assertion is correct but reason is incorrect (D) If assertion is incorrect but reason is correct 1 7 . Which one of the following alkenes will react fastest with H2 under catalytic hydrogenation condition - [IIT-2000] RR RH RR RR (A) (B) (C) (D) R H HR HR HR 1 8 . Propyne and propene can be distinguished by - [IIT-2000] (D) AgNO3 in ammonia (A) conc. H2SO4 (B) Br2 in CCl2 (C) dil.KMnO4 1 9 . Read the following statement and explanation and answer as per the option given below : [IIT-2001] Assertion : Addition of bromine to trans–2–butene yields meso–2, 3–dibromobutane. Reason : Bromine addition to an alkene is an electrophilic addition. (A) If both assertion and reason are correct, and reason is the correct explanation of the assertion (B) If both assertion and reason are correct, but reason is not correct explanation of the assertion (C) If assertion is correct but reason is incorrect (D) If assertion is incorrect but reason is correct
2 0 . In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti-Markovnikov addition to alkene because - [IIT-2001] (A) Both are highly ionic (B) One is oxidising and the other is reducing (C) One of the step is endothermic in both the cases (D) All the steps are exothermic in both cases 2 1 . The reaction of propene with HOCl proceeds via the addition of - [IIT-2001] (A) H+ in the first step (B) Cl+ in first step (C) OH– in first step (D) Cl+ and OH– in single step 2 2 . The nodal plane in the -bond of ethene is located in - [IIT-2001] (A) the molecular plane (B) a plane parallel to the molecular plane (C) a plane perpendicular to the molecular plane which contains the carbon-carbon -bond at right angle (D) a plane perpendicular to the molecular plane which contains the carbon-carbon -bond 2 3 . Consider the following reaction H3C–CH–CH–CH3+Br X + HBr. Identify the structure of major product X : D CH3 [IIT-2002] (A) H3C–CH–CH–CH2 (B) H3C–CH–C–CH3 (C) H3C–C–CH–CH3 (D) H3C–CH–CH–CH3 D CH3 CH3 D CH3 D CH3 2 4 . Identify a reagent from the following list which can easily distinguish between 1–butyne and 2–butyne : (A) Bromine, CCl4 (B) H2, Lindlar catalyst [IIT-2002] (C) dilute H2SO4, HgSO4 (D) ammonical Cu2Cl2 solution 25. C6H5—CC—CH3 HH2gSSOO44 A [IIT-2003] O (A) (B) O (C) C6H5–C=CHCH3 (D) C6H5–CH=C–CH3 OH OH OH HH2O X (Mixture ) Br2 5 26. compounds of molecular formula C4H8Br2.No. of compounds X will be [IIT-2003] (A) 2 (B) 3 (C) 4 (D) 5 2 7 . 2–hexyne can be converted into trans –2–hexene by the reaction of - [IIT-2004] (A) H2–Pd–BaSO4 (B) Li in Liquid NH3 (C) H2–PtO2 (D) NaBH4 2 8 . 1–Bromo–3–chloro cyclobutane on reaction with 2–equivalent of sodium in ether gives - [ IIT- 2005] Br Cl (C) (D) (A) (B) 2 9 . CH3–CH=CH2 NOCl Product, product is : [IIT-2006] (A) CH3–CH–CH2–NO (B) CH3–CH–CH2–Cl Cl NO (C) CH3–CH2–CH2–Cl (D) NO–CH2–CH2–CH2–Cl
3 0 . Cyclohexene on ozonolysis followed by reaction with zinc dust and water gives compound E. Compound E on further treatment with aqueous KOH yields compound F. Compound F is : [IIT-2007] (A) CHO (B) CHO (C) COOH (D) CO2H CO2H 3 1 . Complete the following, giving the structures of the principal organic products. [IIT 1997] Ph H (b) + CHBr3 + t-BuOK B (a) Br + KNH2 A Ph 3 2 . Match the following : [IIT 2006] (A) Ph–CH2–CH2–Br (p) E1 reaction & Ph–CD2–CH2–Br reacts with the same rate. (B) Ph–CH–CH3 reacts faster (q) E2 reaction Br than Ph–CH–CD3 Br (C) Ph–CH2–CH2–Br (r) E 1 reaction cb Ph–CD=CH2 Br (s) 1st order reaction (D) CH3–CH–CD3 CH2=CH–CD3 (Major Product) Cl | (CH 3 )2 C CH 2 CH 3 alc.KOH ? 33. [IIT-1992] 34. C 6 H 5CH 2|CHCH 3 alc.KOH ? HBr ? [IIT-1993] heat Br 3 5 . C(C6H12), an optically active hydrocarbon which on catalytic hydrogenation gives an optically inactive compound, C6H14. [IIT-1993] 3 6 . Draw the stereochemical structure of the product in the following reactions. [IIT-1994] R C C R LindlaHr c2atalyst 3 7 . Write down the structure of the stereoisomers formed when cis-2-butene is reacted with bromine. [IIT-1995] 3 8 . An organic compound E(C5H8) on hydrogenation gives compound F(C5H12). Compound E on ozonolysis gives formaldehyde and 2-ketopropanal. Deduce the structure of compound E. [IIT-1995] 3 9 . Give the structures of the major organic products from 3-ethyl-2-pentene under each of the following reaction conditions. [IIT-1996] (a) HBr in the presence of peroxide (b) Br2/H2O (c) Hg (OAc)2/H2O; NaBH4
4 0 . An alkyl halide, (X) of formula C6H13Cl on treatment with potassium tertiary butoxide gives two isomeric alkenes (Y) and (Z) (C6H12). Both alkenes on hydrogenation give 2, 3-dimethylbutane. Predict the structures of (X), (Y) and (Z). [IIT-1996] 4 1 . 3, 3-Dimethyl-butan-2-ol loses a molecule of water in the presence of concentrated sulphuric acid to give tetramethylethylene as a major product. Suggest a suitable mechanism. [IIT-1996] 4 2 . One mole of the compound A (molecular formula C8H12), incapable of showing stereoisomerism, reacts with only one mole of H2 on hydrogenation over Pd. A undergoes ozonolysis to give a symmetrical diketone B (C8H12O2). What are the structure of A and B ? [IIT-1997] 4 3 . Compound (A) C6H12 gives a positive test with bromine in carbon tetrachloride. Reaction of (A) with alkaline KMnO4 yields only (B) which is the potassium salt of an acid. Write structure formulae and IUPAC name of (A) and (B). [IIT-1997] 4 4 . The central carbon-carbon bond in 1, 3-butadiene is shorter than that of n-butane. Why ? [ IIT- 1998] 4 5 . Write the intermediate steps for the following reaction. [IIT-1998] C6H5CH(OH)CCH C6H5CH=CHCHO [IIT-1998] 4 6 . Write the intermediate steps for the following reaction. H O CH3 OH [IIT-1999] 4 7 . Complete the following - 1. 2. 3. [IIT-1999] 4 8 . Complete the following- DD HO CH3 C=C D–C–C–H H3C–C D H3C C H 4. 5. 6. CH3 CH3 H3C CH3 4 9 . Carry out the following transformation in not more than three steps. [IIT 1999] O [IIT 2000] CH3–CH2–CC–H CH3–CH2–CH2– C–CH3 [IIT 2000] 5 0 . CH2=CH– is more basic than HCC–. Why ? 5 1 . What would be the major product in each of the following reaction ? CH3 H2 Lindilar 's Catalyst 5 2 . On reaction with 4N alcoholic KOH at 175ºC 1-pentyne is slowly converted into equilibrium mixture of 1.3% 1-pentyne (A), 95.2% 2-pentyne (B) and 3.5% 1, 2-pentadiene (C). Give the suitable mechanism of formation of A, B and C with all intermediates. [IIT-2001]
5 3 . Identify X, Y and Z in the following synthetic scheme and write their structure. Is the compound Z optically active ? Justify your answer. [IIT-2002] CH3CH2CC–H (i)NaNH2 X H2/ PdBaSO4 Y Alkaline KMnO4 Z (ii)CH3CH2Br 54. OO Q.55 || || HCHO and CH3 C C H are the products obtained on ozonolysis of a monomer (A) of a polymer. (a) Give the structure of (A) [IIT-2005] (b) Draw the all \"cis\" form of a polymer of a monomer (A) When Phenyl Magnesium Bromide reacts with tert. butanol, which of the following is formed? (A) Tert. butyl methyl ether (B) Benzene (C) Tert. butyl benzene (D) Phenol [IIT ‘2005] Q.56 1–bromo–3–chlorocyclobutane when treated with two equivalents of Na, in the presence of ether which of the following will be formed? [IIT ‘2005] (A) (B) (C) (D) Q.57 CH3–CH=CH2 + NOCl P [IIT 2006] Identify the adduct. CH3 CH CH2 [IIT 2007] (B) | | [IIT 2007] CH3 CH CH2 [IIT 2007] (A) | | NO Cl Cl NO NO | CH2 CH2 CH2 (D) | | (C) CH3 CH2 CH | NO Cl Cl Q.58 The number of stereoisomers obtained by bromination of trans-2-butene is (A) 1 (B) 2 (C) 3 (D) 4 Q.59 The number of structural isomers for C6H14 is (A) 3 (B) 4 (C) 5 (D) 6 Q.60 The reagent(s) for the following conversion, ? H H is / are (A) alcoholic KOH (B) alcoholic KOH followed by NaNH2 (C) aqueous KOH followed by NaNH2 (D) Zn / CH3OH Q.61 The synthesis of 3-octyne is achieved by adding a bromoalkane into a mixture of sodium amide and an alkyne. The bromoalkane and alkyne respectively are [IIT-2010] (A) BrCH2CH2CH2CH2CH3 and CH3CH2CCH (B) BrCH2CH2CH3 and CH3CH2CH2CCH (C) BrCH2CH2CH2CH2CH3 and CH3CCH (D) BrCH2CH2CH2CH3 and CH3CH2CCH
PREVIOUS YEARS QUESTIONS ANSWER KEY EXERCISE -5[B] 1. (C) 2. (A) 3. (A) 4.(C) 5. (A) 6. (A) 7.(B) 8. (D) 9. (A) 10. (C) 11. (B) 12. (A) 13. (B) 14. (B) 15. (A) 16. (C) 17. (A) 18. (D) 19. (B) 20. (C) 21. (B) 22. (C) 23. (B) 24. (D) 25. (A) 26. (B) 27. (B) 28. (C) 29. (A) 30. (B) 33. CH3 —C=CH—CH3 CH3 Br Br CH—CH2—CH3 CH2 —CH—CH3 34. alc. KOH HBr heat H RR 36. C=C 35. CH3—CH2—C—CH=CH2 HH CH3 (C6H12) Br Br 3 7 . H3C H CH3 CH3 H H 38. (E) CH3—C—CH=CH2 H + H CH3 CH2 Br Br (±) Br OH Br (c) (C H ) C—OH 3 9 . (a) (CH3—CH2)2CH—CH—CH3 (b) (CH3—CH2)2C—CH—CH3 2 53 CH3CH3 CH3 CH3 CH3 4 0 . (x) CH3—C—CH—CH3 (Y) CH2=C–—CH—CH3 (Z) CH3—C=C—CH3 Cl O CH3 4 2 . (a) (b) O 4 3 . (A) CH —CH —CH=CH—CH —CH (3-Hexene) 32 23 O (B) CH3—CH2—C—OH (propanoic acid) 4 7 . 1 ozonolysis ; 2 LiAlH4 ; 3 H2SO4 4 8 . (4) HO–Cl ; (5) CH MgCl ; (6) H O/H+ 3 2 51. —CH2 C=C CH3 H H
5 3 . (x) Et–CC–Et Et Et Et (Y) H C=C H H———OH (Z) H———OH Et (Z) is meso compound so optically inactive. CH3—C–CH=CH2 b. CH3 H CH2 CH3 H 5 4 . a. (A) CH2 C=C C=C CH2 C=C CH2 H CH2 CH3 55. (B) 56. (D) 57. (A) 58.(A) 59. (C) 60. (B) 61. (D)
CHECK YOUR GRASP EXERCISE-I HYDROGEN, POLYMER, CHEMISTRY IN EVERYDAY LIFE & EN VIRONMENTAL CHEMISTRY DIHYDROGEN WATER (H2O) 1 . The sum number of neutrons and protons in one of 1 0 . Both temporary and permanent hardness in water the isotopes of hydrogen is :- is removed by :- (1) 3 (2) 4 (3) 5 (4) 6 (1) Boiling (2) Filtration 2 . The catalyst used in Bosch process of manufacture (3) Distillation (4) Decantation of H is :- 11 . Both temporary and permanent hardness is 2 (1) Finely divided Ni (2) V O removed on boiling water with :- 25 (3) Pb (4) Fe O + Cr O 23 23 (1) Ca(OH) (2) Na CO 2 23 3 . The most abundant isotope of hydrogen is :- (1) Tritium (2) Deuterium (3) CaCO (4) CaO 3 (3) Protium (4) Para hydrogen 1 2 . Temporary hardness is caused due to the presence 4 . The n/p ratio for H1 is :- of :- 1 (1) CaSO (2) CaCl (1) 1 (2) 2 (3) 3 (4) Zero 4 2 (3) CaCO (4) Ca(HCO ) 3 32 5. Ordinary hydrogen at room temperature is a 1 3 . High boiling point of water is due to :- mixture of :- (1) Its high specific heat (1) 75% o-Hydrogen + 25% p-Hydrogen (2) Hydrogen bonding (2) 25% o-Hydrogen + 75% p-Hydrogen (3) High dielectric constant (3) 50% o-Hydrogen + 50% p-Hydrogen (4) Low dissociation constant (4) 1% o-Hydrogen + 99% p-Hydrogen HYDROGEN PEROXIDE (H2O2) 6 . In all its properties, hydrogen resembles :- 1 4 . Hydrogen peroxide is not :- (1) Alkali metals only (1) A reducing agent (2) An oxidising agent (2) Halogens only (3) A dehydrating agent (4) A bleaching agent (3) Both alkali metals and halogens 1 5 . The bleaching properties of H O are due to its :- (4) Neither alkali metals nor halogens 22 (1) Reducing properties (2) Oxidising properties 7 . Hydrogen is :- (3) Unstable nature (4) Acidic nature (1) Electropositive 1 6 . Hydrogen peroxide has a :- (2) Electronegative (1) Linear structure (3) Both electropositive as well as elecctro-negative (2) Pyramidal structure (4) Neither electropositive nor electronegative (3) Closed book type structure 8 . Which of the following will not produce hydrogen (4) Half open book type structure gas :- 1 7 . Hydrogen peroxide is a :- (1) Reaction between Fe and dil. HCl (1) Liquid (2) Gas (2) Reaction between Zn and conc. H SO (3) Solid (4) Semi-solid 24 (3) Reaction between Zn and NaOH 1 8 . Which of the following is a true structure of H O (4) Electrolysis of NaCl in Nelson's cell 22 9 . Para hydrogen is :- (1) Less stable than ortho hydrogen 180° H 94.8° (2) O O (1) H O O H H (2) More stable than ortho hydrogen H H (3) As stable as ortho hydrogen (3) O O (4) O=O H H (4) None of these
1 9 . Decomposition of H O is retarded by :- CH3 22 (1) Acetanilide (2) MnO 2 2 6 . Monomer of— C—CH2— is – (3) Zinc (4) Finely divided metals 2 0 . H O is :- CH3 n 22 (1) An oxiding agent (2) Both oxidising and reducing agent (1) 2–methyl propene (2) Styrene (3) Reducing agent (3) Propylene (4) Ethene (4) None of the above 27. Acrylon is a hard, horny and a high melting material. Which of the following represents its 2 1 . H O is :- (2) Paramagnetic structure - 22 (1) Diamagnetic (3) Ferromagnetic (4) None of these 2 2 . The hybridisation of the orbitals of oxygen in H O CH3 22 is :- (1) CH2 CH (2) CH2 C (1) sp3d (2) sp (3) sp2 (4) sp3 CN COOC2H5 n 2 3 . H O is always stored in black bottles because :- n 22 (1) It is highly unstable (2) Its enthalpy of decomposition is high CH2 CH CH2 CH (3) It undergoes autooxidation on prolonged (3) (4) COOC2H5 n Cl n standing (4) None of these 2 8 . Which one of the following monomers gives the polymer neoprene on polymerization – P O LY M E R (1) CH2 CHCl (2) CCl2 CCl2 Cl 2 4 . CF CF is a monomer of – 22 (1) Teflon (2) Orlon (3) CH2 C CH CH2 (3) Polythene (4) Nylon–6 2 5 . Which of the following is not correctly matched – (4) CF2 CF2 2 9 . Which of the following is a biodegradable polymer (1) Cellulose (2) Polythene (1) Neoprene CH2 C CH CH2 (3) Polyvinyl chloride (4) Nylon-6 Cl n 30 . Which one of the following is a chain growth polymer (1) Nucleic acid (2) Polystyrene O (3) Protein (4) Starch (2) Nylone–66 –NH(CH2)6NHCO(CH2)4C– 3 1 . The monomer of the polymer – n O O CH2 CH3 C CH3 (3) Terylene –OCH2–CH2–C– C CH2 CH3 is –C– CH3 n (1) CH3CH CHCH3 (2) CH3CH CH2 CH3 (3) (CH3)2C C(CH3)2 (4) H2C C CH3 (4) PMMA –CH2–C– CH3 COOCH3 n 3 2 . Which one of the following polymers is prepared by condensation polymerization (1) Styrene (2) Nylon–66 (3) Teflon (4) Rubber
CHEMISTRY IN EVERYDAY LIFE 4 4 . Biosphere is (1) In which individual interact to each other 3 3 . An antipyretic is – (2) By which life originated (1) Quinine (2) Paracetamol (3) The name of a bird (3) Luminal (4) Piperazine (4) Organic compound by which life diminishes 3 4 . Medicine which is an antibiotic is – 4 5 . Which is not a renewable source (1) Ampicillin (2) Aspirin (1) Forest (2) Coal (3) Chloroquine (4) None of these (3) Water (4) Forest organism 3 5 . Alizarin belongs to the class of – 4 6 . Noosphere is synonyms of (1) Vat dyes (2) Mordant dyes (1) Environment (2) Atmosphere (3) Substantive dyes (4) Reactive dyes (3) Hydrosphere (4) Stratosphere 3 6 . Which of the following is a basic dye – 47 . When biosphere turns into human dominated (1) Alizarin (2) Phthalein environment it is called (3) Aniline yellow (4) Orange-I (1) Noosphere (2) Troposphere 3 7 . Diazo coupling is useful to prepare some – (3) Mesosphere (4) Man sphere (1) Pesticides (2) Dyes 4 8 . The living organisms on or around the earth consitute (3) Proteins (4) Vitamins (1) Biome (2) Biosphere 3 8 . Which of the following is an azo dye – (3) Community (4) Biocoenosis (1) Methyl orange (2) Phenolphthalein 4 9 . Biosphere refers to (3) Malachite green (4) Methylene blue (1) Plants of the world 3 9 . Paracetamol is a/an – (2) Special plants (1) Both antipyretic and analgesic (3) Area occupied by living beings (2) Analgesic (3) Antipyretic (4) Plants of a particular area (4) Antimalarial 5 0 . What is the correct sequence of atmospheric layers 4 0 . Which of the following compounds is aspirin – starting from earth (1) Methyl salicylate (2) Acetylsalicylic acid (1) Stratosphere troposphere, mesosphere, (3) Phenyl salicylate (4) Salicylic acid thermosphere 4 1 . Sulpha drugs are derivatives of – (2) Troposphere, startosphere, mesosphere, (1) Benzene sulphonic acid (2) Sulphanillic acid thermosphere (3) Sulphanilamide (4) p - aminobenzoic acid (3) Mesosphere, troposphere, stratosphere, 4 2 . Which of the following is a natural dye – thermosphere (1) Phenolphthalein (2) Alizarin (4) Thermosphere, mesophere, stratosphere, (3) Martius yellow (4) Malachite green troposphere 5 1 . On earth all living organisms constitute ENVIRONMENTAL CHEMISTRY (1) Community (2) Biome 4 3 . The term biosphere is used for the zone of the earth (3) Association (4) Biosphere where life exists (1) On the lithospere 5 2 . A biosphere is composed of (2) In the hydrosphere (3) In the lithosphere and hydrosphere (1) Living organisms (4) In the lithosphere, hydrosphere and atmosphere (2) Living organisms + Lithosphere (3) Living organisms + lithosphere + atmosphere (4) Living organisms + lithosphere + atmosphere hydrosphere CHECK YOUR GRASP ANSWER KEY EXERCISE-I Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans 1 4 3 4 1 3 3 2 1 3 2 4 2 3 2 Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans 4 1 2 1 2 1 4 3 1 3 1 1 3 1 2 Que. 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Ans 4 2 2 1 2 3 2 1 1 2 3 2 4 1 2 Que. 46 47 48 49 50 51 52 Ans 1 1 2 3 2 4 4
BRAIN TEASERS EXERCISE-II HYDROGEN, POLYMER, CHEMISTRY IN EVERYDAY LIFE & EN VIRONMENTAL CHEMISTRY 1 . The function of enzymes in the living system is to – 1 0 . Among the following a natural polymer is - (1) Transport oxygen (1) Cellulose (2) PVC (2) Provide immunity (3) Teflon (4) Polyethylene 1 1 . Which is a naturally occuring polymer- (3) Catalyse biochemical reaction (1) Polythene (2) PVC (4) Provide energy (3) Acetic acid (4) Protein 2 . Enzymes are :- 1 2 . Which one of the following is a linear polymer- (1) Carbohydrates (2) Nucleic acids (1) Amylopectin (2) Glycogen (3) Globular proteins (4) Fibrous proteins (3) Starch (4) Amylose 3 . The sex hormone which controls the development 1 3 . Natural rubber is which type of polymer- and maintenance of pregnancy is :- (1) Condensation polymer (2) Addition polymer (1) Cortisone (2) Thyroxine (3) Co-ordination polymer (4) None of these (3) Progesterone (4) Estrone 1 4 . Polyethylene is - 4 . Vitamin E is also called :- (1) Random copolymer (1) Cyanocobalamin (2) tocopherol (2) Homo polymer (3) Lactoflavin (4) Ascorbic acid (3) Alternate copolymer 5 . The deficiency of vitamin K causes :- (4) Crosslinked copolymer (1) Haemorrhage 1 5 . Nylon is not a - (2) Lenghening time of blood clotting (1) Condensation polymer (3) Inflammation of tung (2) Polyamide (4) Both (1) and (2) (3) Copolymer 6 . The function of haemoglobin is to :- (4) Homopolymer (1) Help in muscular moment 1 6 . Bakelites are - (2) Store oxygen until it is needed for energy (1) Rubber (2) Rayon reproduction (3) Resins (4) Plasticisers (3) Transport oxygen from lungs to various tissues 1 7 . Which of the following is a basic dye – through blood stream (1) Alizarin (2) Malachite green (4) Catalyse biochemical processes (3) Indigo (4) Orange-I 7 . Which one among the following is a thermosetting plastic - 1 8 . The compound used to fix a dye to the fabric is (1) PVC (2) PVA called – (3) Bakelite (4) Perspex (1) Mordant (2) Lake (4) Oxidising agent 8 . The basis on the mode of their formation, the (3) Bleaching agent polymers can be classified - (1) As addition polymers only 1 9 . Aspirin is called – (2) As condensation polymers only (1) Pyretic (2) Antiseptic (3) As copolymers (3) Antibiotic (4) Antipyretic (4) Both as addition and condensation polymers 2 0 . Which of the following is an antidiabetic drug – 9 . Which of the following is not a polymer - (1) Insulin (2) Penicillin (3) Chloroquine (4) Aspirin (1) Gun cotton (2) Perspex (3) Shellac (eg. lac shellac)(4) Wax (eg. bees wax)
2 1 . 2-Acetoxybenzoic acid is called – 2 9 . Petroleum resource is (1) Antiseptic (2) Aspirin (1) Renewable (3) Antibiotic (4) Mordant dye (2) Non renewable 2 2 . Match List-I with List-II and select the correct answer (3) Synthetic & biodegradable using the codes given below the lists – (4) Infinite & unconventional List I List II 3 0 . The main aim of plant conservation is - I. Iodoform A. Anaesthetic (1) To conserve the necessary ecological activities and life supporting systems II. Methyl salicylate B. Antiseptic III. Diethyl ether C. Insecticide (2) To conserve species diversity and range of genetic meterial IV. Hexachlorocyclohexane D. Detergent E. Pain Balm (3) Both the above (1) I–B, II–E, III–C, IV–D (4) None of the above (2) I–D, II–B, III–A, IV–C 3 1 . Environmental laning organisation is (3) I–B, II–E, III–A, IV–C (1) CSIR (2) CEPHERI (4) I–C, II–A, III–D IV–B (3) ICAR (4) NEERI 2 3 . Arsenic drugs are mainly used in the treatment of– 3 2 . Which will not cause any atmospheric pollution (1) Jaundice (2) Typhoid (1) Hydrogen (2) Sulphur dioxide (3) Syphilis (4) Cholera (3) Carbon dioxed (4) Carbon monoxide 2 4 . Aspirin is an acetylation product of – 3 3 . Which of the following is the main factor of water pollution (1) p-dihyroxybenzene (2) o-hydroxybenzoic acid (1) Smoke (2) Industrial waste (3) Detergent (4) Ammonia (3) o-dihydroxy benzene (4) m-hydroxybenzoic acid 3 4 . Main air pollutant among the following is 2 5 . An example of vat dye is – (1) CO (2) CO (3) N (4) Sulphur 2 2 (1) Indigo (2) Alizarin 3 5 . Which is more important for water pollution (3) Malachite green (4) Martius yellow (1) Sound (2) SO2 2 6 . Which of the following is an azo dye – (3) Salts of arsenic (4) Sewage (1) Orange - I (2) Malachite green 3 6 . Which of the following atmospheric pollutants is not (3) Indigo (4) Martius yellow produced by the exhaust of motor vehicle in Delhi 2 7 . Which of the following is the non conventional source (1) SO (2) Hydrocarbon gases of energy 2 (4) CO (3) Fly ash (1) Coal 3 7 . Riboflavin is the chemical name of :- (2) Petroleum (1) Vitamin B (2) Vitamin B 1 2 (3) Electricity from nuclear power plants (3) Vitamin B (4) Vitamin B complex 6 (4) Solar radiations 3 8 . Calorific value is in the order :- 2 8 . The population of India is 15% of the world but its (1) Fats > Carbohydrates > Proteins annual energy consumption is only (2) Carbohydrates > Fats > Proteins (1) 0.2% (2) 2.0% (3) Proteins > Carbohydrates > Fats (3) 10% (4) 25% (4) Fats > Proteins > Carbohydrates
3 9 . Which of the following is a step growth polymer- 4 9 . The synthetic polymer which resembles natural rubber is - (1) Polyisoprene (2) Polythene (3) Nylon (4) Polyacrylonitrile (1) Neoprene (2) Chloroprene 4 0 . An example of chain growth polymer is (3) Glyptal (4) Nylon (1) Nylon -66 (2) Bakelite 5 0 . Chloramphenicol is an – (3) Terylene (4) Teflon (1) Analgesic (2) Anaesthetic (3) Antibiotic (4) Antiseptic 4 1 . Which of the following is not an example of natural polymer- 5 1 . Detergents are prepared by the action of H SO 24 (1) Wool (2) Silk followed by neutralization by starting with– (3) Leather (4) Nylon (1) Cholesterol (2) Lauryl alcohol (3) Cyclohexanol (4) p-Nitrophenol 4 2 . Natural rubber is a - (1) Polyester (2) Polyamide 5 2 . 2, 4, 6 – trinitrophenol is a/an – (3) Polyisoprene (4) Polysaccharide (1) Acid dye (2) Basic dye (3) Azo dye (4) Vat dye 4 3 . Which of the following is not a synthetic polymer - 5 3 . Substances which bring body temperature down are known as – (1) Polyethylene (2) PVC (3) Nylon (4) Cellophane (1) Antipyretics (2) Analagin (3) Antibiotics (4) Hypnotics 4 4 . Which of the following is not correct regarding terylene - 5 4 . The indicator used in the titration of a strong acid and a strong base is – (1) Step -growth polymer (2) Synthetic fibre (1) Phenolphthalein (2) Methyl Orange (3) Alizarin yellow (4) Red litmus (3) Condensation polymer (4) Thermosetting plastic 5 5 . The drug given during hypertension is – 4 5 . When heated with zinc chloride. lactides forms a (1) Streptomycin (2) Chloroxylenol linear polymer which may be - (3) Equanil (4) Aspirin (1) Polystyrene (2) Polyamide 5 6 . One of the most widely used drug in medicine iodex is (3) Polyester (4) Polythene 4 6 . The catalyst used for the polymerisation of olefins (1) Methyl salicylate (2) Ethyl salicylate is - (3) Acetylsalicylic acid (4) o-hydroxybenzoic acid (1) Ziegler Natta catalyst (2) Wilkinson's catalyst 5 7 . Which of the following is known as broad spectrum antibiotic – (3) Pd-catalyst (4) Zeise's salt catalyst 4 7 . PVC is prepared by the polymerisation of - (1) Streptomycin (2) Ampicillin (3) Chloramphenicol (4) Penicillin (1) Ethylene (2) 1-chloropropene (3) Propene (4) 1-chloroethene 5 8 . Phenol is used as – 4 8 . Acrylonitrile forms - (1) An antiseptic (2) A disinfectant (3) Both (1) and (2) (4) None of these (1) Terylene (2) Orlon 5 9 . The antiseptic action of dettol is due to – (3) PVC (4) Bakelite (1) Chloro benzene (2) Chloroxylenol (3) Chloroquine (4) Chloramphenicol
6 0 . Pollution can be controlled by 6 6 . Removal of the soil by the action of wind and water is known as (1) Sewage treatment (2) Checking atomic blasts (1) Erosion (2) Fossilization (3) Manufacturing electrically operated vehicles (3) Leaching (4) Calcification (4) All the above 6 7 . Acid rain occure due to atmospheric pollution of 6 1 . If water pollution continues at its present rate, it (1) SO (2) NH will eventually 2 3 (3) CO (4) N O 2 2 (1) Stop water cycle 6 8 . Photochemical smog was first observed in - (2) Prevent precipitation (1) London (2) Lons Angeles (3) Make oxygen molecules unavailable to water (3) Paris (4) Tokyo plants. 6 9 . An increase in CO concentration in the atmosphere (4) Make nitrate molecules unavailable to water 2 plants. will result in (1) Adverse effects of natural vegetation 6 2 . In cities like Bombay and Calcultta the major air (2)Global warming pollutants are (3) Temperature decrease in global atmosphere (1) Ozone (4) Genetic disoders in plants and animals (2) Carbon monoxide and oxides of Sulphur 7 0 . Calgon is an industrial name given to :- (3) Hydrocarbons and not air (1) Normal sodium phosphate (4) Algal spores and marsh gas (2) Sodium meta-aluminate 6 3 . Recent reports of acid rains industrial cities are due (3) Sodium hexametaphosphate to the effect of atmospheric pollution by (4) Hydrated sodium aluminium silicate (1) Excessive release of NO and SO by burning of 7 1 . When the same amount of zinc is treated separately 22 with excess of sulphuric acid and excess of sodium fossil fuels. hydroxide, the ratio of volumes of hydrogen evolved is :- (2) Exessive release of CO by burning of fuel like 2 (1) 1 : 1 (2) 1 : 2 (3) 2 : 1 (4) 9 : 4 wood and charcoal, cutting of forests and 7 2 . Permutit is :- increased animal population. (3) Excessive release of NH by industrial plants (1) Hydrated sodium aluminium silicate 3 and coal gas. (2) Sodium hexametaphosphate (4) Excessive release of CO in atmosphere by (3) Sodium silicate incomplete combustion of cock, charcoal and other carbonaceous fuels in pancity of oxygen, (4) Sodium meta-aluminate 64 . Pollution is a change in physical, chemical or 7 3 . Ortho and Para hydrogen differ :- biological characters of our land and water that may be (1) In the number of protons (2) In the molecular mass (1) Desirable and harmful to human (3) In the nature of spins of protons (2) Desirable and useful to human (4) In the nature of spins of electrons (3) Undesirable and harmful to human 7 4 . In Bosch's process which gas is utilised for the production of hydrogen :- (4) undesirable and useful to human (1) Producer gas (2) Water gas 6 5 . Which is the greatest air pollutant these days (3) Coal gas (4) Natural gas (1) Factories (2) Motor vehicles (3) Domestic appliances (4) animals
7 5 . The gas used in the hydrogenation of oils in presence 8 1 . The adsorption of hydrogen by metals is called :- of nickel as a catalyst is :- (1) Dehydrogenation (2) Hydrogenation (1) Methane (2) Ethane (3) Occlusion (4) Adsorption (3) Ozone (4) Hydrogen 8 2 . Heavy water (D2O) is :- (1) A product of oxygen and hydrogen 7 6 . Water softening by Clarke's process uses :- (1) Calcium bicarbonate (2) Sodium bicarbonate (2) Ordinary water containing dissolved salts of heavy metals (3) Potash alum (4) Calcium hydroxide 7 7 . Which of the following produces hydrolith with (3) Water of mineral springs dihydrogen :- (4) Water produced by repeated distillation and (1) Mg (2) Al (3) Cu (4) Ca condensation 7 8 . The lightest gas is :- 8 3 . Ionic hydrides are usually :- (1) Nitrogen (2) Helium (1) Good electrically conductors when solid (3) Oxygen (4) Hydrogen (2) Easily reduced 7 9 . The ratio of electron, proton and neutron in tritium (3) Good reducing agents is :- (4) Liquid at room temperature (1) 1 : 1 : 1 (2) 1 : 1 : 2 (3) 2 : 1 : 1 (4) 1 : 2 : 1 8 0 . The nuclei of tritium (H3) atom would contain neutrons :- (1) 1 (2) 2 (3) 3 (4) 4 BRAIN TEASERS ANSWER KEY EXERCISE-II Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans 3 3 3 2 4 3 3 4 4 1 4 4 2 2 4 Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans 3 2 1 4 1 2 3 3 2 1 1 4 2 2 3 Que. 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Ans 4 1 2 1 3 3 1 1 3 4 4 3 4 4 1 Que. 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Ans 1 4 2 1 3 2 1 1 1 3 1 3 3 2 4 Que. 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 Ans 3 2 1 3 2 1 1 2 2 3 1 1 3 2 4 Que. 76 77 78 79 80 81 82 83 Ans 4 4 4 2 2 3 4 3
PREVIOUS YEAR QUESTIONS EXERCISE-III HYDROGEN, POLYMER, CHEMISTRY IN EVERYDAY LIFE & EN VIRONMENTAL CHEMISTRY 1 . Which hydride is an ionic hydride :- [AIIMS 1985] 8 . Hydrogen peroxide is now generally prepared on (1) NH (2) H S (3) TiH (4) NaH industrial scale by the :- [Roorkee 1992] 3 2 1.73 2. The reaction, H S + HO S+ 2H O manifests: (1) Action of H SO on barium peroxide 2 22 2 24 [MLNR 1987] (2) Action of H SO on sodium peroxide 24 (1) Acidic nature of H O (3) Electrolysis of 50% H SO 22 24 (2) Alkaline nature of H O (4) Burning hydrogen in excess of oxygen 22 (3) Oxidising nature of H O 9 . The hardness of water is due to..........metal ions 2 (4) Reducing nature of H O [BHU 1992] 22 3 . Heavy water has found application in atomic reactor as :- [MLNR 1988] (1) Ca2+ and Na+ (2) Mg2+ and K+ (1) Coolant (3) Ca2+ and Mg2+ (4) Zn2+ and Ba2+ (2) Moderator 1 0 . Which of the following statement is correct :- (3) Both coolant and moderator [BHU 1997] (4) Neither coolant nor moderator (1) Hydrogen has same ionisation potential as 4 . Calgon (a water softener) is :- [CBSE 1989] sodium (1) Na [Na (PO ) ] (2) Na [Na (PO )] (2) H has same electronegativity as halogens 24 36 42 36 (3) Na [Na (PO )] (4) Na [Na (PO ) ] (3) It will not be liberated at anode 24 46 42 46 5 . Hydrogen peroxide works as :- [CPMT 1990] (4) H has oxidation state + 1, zero and – 1 (1) An oxidant only 1 1 . The formula of heavy water is :- (2) A reductant only [CPMT 1991 ; AFMC 1997] (3) An acid only (1) H O18 (2) D O (3) T O (4) H O17 (4) An oxidant, a reductant and an acid 22 2 2 1 2 . Polyphosphates are used as water softening agent 6 . The hair dyes available in the market generally contain two bottles, one containing the dye and the becuase they :- [IIT 2002] other hydrogen peroxide. Before applying the dye, (1) Form soluble complexes with anionic species the two solutions are mixed. the hydrogen peroxide (2) Precipitate anionic species [NCERT 1990] (3) Form soluble complexes with cationic species (1) Is added to dilute the solution of the dye (4) Precipitate cationic species. (2) Oxidises the dye to give the desired colour 1 3 . Which one of the following processes will produce (3) Reduces the dye to give the the desired colour hard water :- [AIEEE 2003] (4) Acidifies the solution of the dye (1) Saturation of water with CaSO 4 7 . When zeolite (hydrated sodium aluminium silicate) (2) Addition of Na2SO4 to water is treated with hard water, the sodium ions are (3) Saturation of water with CaCO 3 exchanged with :- [IIT 1990] (1) H+ ions (2) Ca2+ ions (4) Saturation of water with MgCO 3 1 4 . In an organic compound of molar mass 108gmol-1 (3) SO 2 ions (4) OH– ions C, H and N atoms are present in 9 : 1 : 35 by 4 wegith. Molecular formula can be- [AIEEE - 2002] (1) C6H8N2 (2) C7H10N (3) C5H6N3 (4) C4H18N3
1 5 . Compound A given below is : 2 1 . The ammonia evolved from the treatment of 0.30g of an organic compound for the estimationof OCOCH3 nitrogen was passed in 100 mL of 0.1 M sulphuric COOH acid. The excess of acid required 20 mL of 0.5 M sodium hydroxide solution for complete [AIEEE - 2002] neutralization. The organic compound is- [AIEEE - 2004] (1) Antiseptic (2) Antibiotic (3) Analgesic (4) Pesticide (1) acetamid (2) benzamide 1 6 . Monomers are converted to polymer by- (3) urea (4) thiourea (1) Hydrolysis of monomer [AIEEE - 2002] 2 2 . Which one of the following types of drugs reduces (2) Condensation reaction between monomers fever- [AIEEE - 2005] (3) protonation of monomers (1) Tranquilizer (2) Antibiotic (4) none of the above (3) Antipyretic (4) Analgesic 1 7 . Nylon treads are made of- [AIEEE - 2003] 2 3 . Which of the following is a polyamide [AIEEE - 2005] (1) polyvinyl polymer (1) Bakelite (2) Terylene (2) polyester polymer (3) Nylon-66 (4) Teflon (3) polyamide 2 4 . Which of the following is fully fluorinated polymer- [AIEEE - 2005] (4) polyethylene polymer 1 8 . Which of the following could act as a propellant (1) PVC (2) Thiokol for rockets- [AIEEE - 2003] (3) Teflon (4) Neoprene (1) Liquid hydrogen + liquid nitrogen 2 5 . An organic compound having molecular mass 60 is found to contain C = 20%, H = 6.67 % and (2) Liquid oxygen + liquid argon N = 46.67 % while rest is oxygen on heating it gives NH3 along with a solid residue. The solid (3) Liquid hydrogen + liquid oxygen residue give violet colour with alkaline copper sulphate solution. The compound is- (4) Liquid nitrogen + liquid oxygen [AIEEE - 2005] 1 9 . Identify the correct statement regarding enzymes- [AIEEE - 2004] (1) Enzymes are specific biological catalysts that (1) CH3CH2CONH2 (2) (NH2)2CO can normally function at very high temperatures (T 1000 K) (3) CH3CONH2 (4) CH3NCO 2 6 . Regular use of which of the following fertilisers (2) Enzymes are normally heterogeneous catalysts increases the acidity of soil ? that are very specific in their action (1) Potassium nitrate [AIEEE - 2007] (3) Enzymes are specific biological catalysts that (2) Urea can not be poisoned (3) Superphosphate of lime (4) Enzymes are specificbiological catalysts that (4) Ammonium sulphate possess well defined active sites 2 7 . Identify the wrong statement in the following (1) Chlorofluorocarbons are responsible for ozone 2 0 . Insulin production and its action in human body layer depletion [AIEEE-2008] are responsible for the level of diabetes. This (2) Greenhouse effect is responsible for global compound belongs to which of the following warming categories [AIEEE - 2004] (3) Ozone layer does not permit infrared radiation (1) A coenzyme (2) A hormone from the sun to reach the earth (3) An enzyme (4) An antibiotic (4) Acid rain is mostly because of oxides of nitrogen and sulphur
2 8 . Buna–N synthetic rubber is a copolymer of :- 30 . 29.5 mg of an organic compound containing [AIEEE-2009] nitrogen was digested according to Kjeldahl's (1) H2C = CH – CN and H2C = CH – CH = CH2 method and the evolved ammonia was absorbed in (2) H2C = CH – CN and H2C = CH – C = CH2 CH3 20 mL of 0.1 M HCl solution. The excess of the acid required 15 mL of 0.1 M NaOH solution for complete neutralization. The percentage of nitrogen Cl in the compound is :- [AIEEE-2010] (3) H2C = CH – C =CH2 and H2C = CH – CH = CH2 (1) 29.5 (2) 59.0 (4) H2C = CH – CH = CH2 and H5C6 – CH = CH2 (3) 47.4 (4) 23.7 29 . The two functional groups present in a typical 3 1 . The polymer containing strong intermolecular forces carbohydrate are :- [AIEEE-2009] e.g. hydrogen bonding, is :- [ A I E E E- 2 0 10 ] (1) >C = O and –OH (1) natural rubber (2) teflon (2) –OH and –CHO (3) nylon 6, 6 (4) polystyrene (3) –OH and –COOH 3 2 . Biurest test is not given by :- [ A I E E E- 2 0 10 ] (4) –CHO and –COOH (1) proteins (2) carbohydrates (3) polypeptides (4) urea PREVIOUS YEAR QUESTIONS ANSWER KEY EXERCISE-III Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans 4 3 3 1 4 2 2 3 3 4 2 3 1 1 3 Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans 2 3 3 4 2 3 3 3 3 2 4 3 1 2 4 Que. 31 32 Ans 3 2
EXERCISE-01 CHECK YOUR GRASP SELECT THE CORRECT ALTERNATIVE (ONLY ONE CORRECT ANSWER) 1 . Which of the following expressions is/are not true ? (A) [H+] = [OH–] = K w for a neutral solution at all temperatures. (B) [H+] > K w & [OH–] < K w for an acidic solution (C) [H+] < K w & [OH–] > K w for an alkaline solution (D) [H+] = [OH–] = 10–7 M for a neutral solution at all temperatures 2 . Addition of HCl will not suppress the ionization of- (A) acetic acid (B) Benzoic acid (C) H2S (D) Sulphuric acid 3 . An acid solution of pH 6 is diluted thousand times. The pH of solution becomes approx- (A) 6.96 (B) 6 (C) 4 (D) 9 4 . pOH of H2O is 7.0 at 298 K. If water is heated at 350 K, which of the following should be true ? (A) pOH will decrease (B) pOH will increase (C) pOH will remain 7.0 (D) concentration of H+ ions will increase but that of OH– will decrease 5 . Which of the following solution will have a pH exactly equal to 8 ? (A) 10–8 M HCl solution at 25°C (B) 10–8 M H+ solution at 25° (C) 2 × 10–6 M Ba(OH)2 solution at 25° C (D) 10–6 M NaOH solution at 50° C 6 . The number of hydrogen ions in 10 mL of a solution with pH = 13 is- (A) 1013 (B) 6.023 × 108 (C) 6.023 × 1013 (D) 6.023 × 1010 7 . At 55° C autoprotolysis constant of water is 4 × 10–14. If a given sample of water has a pH of 6.9, then it is- (A) acidic (B) basic (C) neutral (D) explosive 8 . 0.1 mol HCl is dissolved in distilled water of volume V then V lim (pH)solution is equal to- (A) zero (B) 1 (C) 7 (D) 14 9 . A 50 mL solution of pH = 1 is mixed with a 50 mL solution of pH = 2. then pH of the mixture will be nearly- (A) 0.76 (B) 1.26 (C) 1.76 (D) 2.26 1 0 . The pH of a solution obtained by mixing 50 mL of 0.4 N HCl and 50 mL of 0.2 N NaOH is- (A) – log 2 (B) – log 0.2 (C) 1.0 (D) 2.0 1 1 . The pH of a solution is 7.00. To this solution sufficient base is added to increase the pH to 12.0. The increase OH– ion concentration is- (A) 5 times (B) 1000 times (C) 105 times (D) 4 times 1 2 . Which of the following solution will have pH close to 1.0 ? (A) 100 mL of M/10HCl + 100 mL of M/10 NaOH (B) 55 mL of M/10 HCl + 45 mL of M/10 NaOH (C) 10 mL of M/10 HCl + 90 mL of M/10 NaOH (D) 75 mL of M/5 HCl + 25 mL of M/5 NaOH. 1 3 . The dissociation constants of two acids HA1 and HA2 are 3.0 × 10–4 and 1.8 × 10–5 respectively. The relative strengths of the acids will be approximately- (A) 1 : 4 (B) 4 : 1 (C) 1 : 16 (D) 16 : 1
1 4 . Which of the following is true- (A) pkb for OH– is – 1.74 at 25°C (B) the equilibrium constant for the reaction between HA (pKa = 4) and NaOH at 25°C will be equal to 1010 (C) the pH of a solution containing 0.1 M HCOOH (ka = 1.8 × 10–4) and 0.1 M HOCN. (ka = 3.2 × 10–4) will be nearly (3 – log 7). (D) all the above are correct. 1 5 . Which statement/relationship is correct ? (A) upon hydrolysis of salt of a strong base and weak acid gives a solution with pH < 7 1 (B) pH = –log [H ] (C) only at 25 °C the pH of water is 7 (D) the value of pKw at 25 °C is 7 1 6 . If 50 mL of 0.2 (M) KOH is added to 40 mL of 0.5(M) HCOOH. The pH of the resulting solution is (K = 1.8 × 10–4) : (A) 3.75 (B) 5.6 (C) 7.5 (D) 3.4 1 7 . 50% neutralization of a solution of formic acid (Ka = 2 × 10–4) with NaOH would result in a solution having a hydrogen ion concentration of- (A) 2 × 10–4 (B) 3.7 (C) 2.7 (D) 1.85 1 8 . The correct order of increasing [H3O+] in the following aqueous solution is- (A) 0.01 M H2S < 0.01 M H2SO4 < 0.01 M NaCl < 0.01 M NaNO2 (B) 0.01 M NaCl < 0.01 M NaNO2 < 0.01 M H2S < 0.01 M H2SO4 (C) 0.01 M NaNO2 < 0.01 M NaCl < 0.01 M H2S < 0.01 M H2SO4 (D) 0.01 M H2S < 0.01 M NaNO2 < 0.01 M NaCl < 0.01 M H2SO4 1 9 . The sodium salt of a certain weak monobasic organic acid is hydrolysed to an extent of 3% in its 0.1 M solution at 25 °C. Given that the ionic product of water is 10–14 at this temperature, what is the dissociation constant of the acid ? (A) 1 × 10–10 (B) 1 × 10–9 (C) 3.33 × 10–9 (D) 3.33 × 10–10 2 0 . The correct order for the increasing extent of hydrolysis is- (A) P O 3 – < H P O 2– < H 2P O – (B) H P O – < H P O 2 – < P O 3 – 4 4 4 4 4 4 2 (C) H P O 2– < P O 3– < H 2P O – (D) P O 3 – < H 3P O – < H P O 2 – 4 4 4 4 4 4 2 1 . The correct order of increasing pH of decimolar solution of each of the following in- (A) NH4NO3 < NaNO3 < NaHCO3 < Na2CO3 (B) NaNO3 < NH4NO3 < NaHCO3 < Na2CO3 (C) NaNO3 < NH4NO3 < Na2CO3 < NaHCO3 (D) Na2CO3 < NaHCO3 < NaNO3 < NH4NO3 2 2 . When 100 mL of 0.4 M CH3COOH are mixed with 100 mL of 0.2 M NaOH, the [H3O+] in the solution is approximately : [Ka(CH3COOH) = 1.8 × 10–5] (A) 1.8 × 10–6 (B) 1.8 × 10–5 (C) 9 × 10–6 (D) 9 × 10–5 2 3 . A solution is 0.1 M CH3COOH and 0.1 M CH3COONa. Which of the following will change the pH significantly, of the solution ? (A) addition of water (B) addition of CH3COONa without change in volume (C) addition of CH3COOH without change in volume (D) none will change the pH significantly
2 4 . What will be the pH at the equivalence point during the titration of a 100 mL 0.2 M solution of CH3COONa with 0.2 M solution of HCl ? Ka = 2 × 10–5 (A) 3 – log 2 (B) 3 + log 2 (C) 3 – log2 (D) 3 + log 2 2 5 . Ka for HCN is 5 × 10–10 at 25 °C. For maintaining a constant pH of 9, the volume of 5 M KCN solution required to be added to 10 mL of 2M HCN solution is- (A) 4 mL (B) 7.95 mL (C) 2 mL (D) 9.3 mL 2 6 . The pH of a solution obtained by mixing 100 mL of 0.2 M CH3COOH with 100 mL of 0.2 M NaOH would be (pKa for CH3COOH = 4.74 and log 2 = 0.301) (A) 4.74 (B) 8.87 (C) 9.10 (D) 8.57 2 7 . Which of the following when added to 1.0 L of 0.5 M HCl would result in maximum increase in pH ? (A) 0.5 mol CH3COOH (B) 1.0 mol NaCl (C) 0.4 mol NaOH (D) 0 .6 mole CH3COONa 2 8 . What % of the carbon in the H2CO3, HCO3–. Buffer should be in the form of HCO3– so as to have a neutral solution ? (Ka = 4 × 10–7) (A) 20 % (B) 40 % (C) 60 % (D) 80 % 2 9 . Which of the following solution would have same pH ? (A) 100 mL of 0.2 M HCl + 100 mL of 0.4 M NH3 (B) 50 mL of 0.1 M HCl + 50 mL of 0.2 M NH3 (C) 100 mL of 0.3 M HCl + 100 mL of 0.6 M NH3 (D) All will have same pH 3 0 . 50 mL of 0.1 M NaOH is added to 60 mL of 0.15 M H3PO4 solution (K1, K2 and K3 may be taken as 10–3, 10–8 and 10–13 respectively). The pH of the mixture would be about- (A) 3.1 (B) 5.5 (C) 4.1 (D) 6.5 3 1 . The solubility of a certain sparingly soluble substance MXn is nearly 1.4 × 10–4 M. If the solubility product is 1.1 × 10–11, what is the value of n ? (A) 1 (B) 2 (C) 3 (D) 1.5 3 2 . The concentration of Mg2+ in the solution made by mixing 10 mL of 0.25 M Mg(NO3)2 and 25 mL of 0.2 M NaF will be (Ksp(MgF2 = 8 × 10–8) (A) 0.0027 M (B) 0.0714 M (C) 0.0030 M (D) 0.0060 M 3 3 . The pH of a saturated solution of Mg(OH)2 in water will be (Ksp = 4 × 10–12) (A) 4 – log 2 (B) 10 – log 2 (C) 4 + log 2 (D) 10 + log 2 3 4 . When NaCl is added to the reaction mixture of an oil and caustic soda, the soap is thrown out because- (A) NaCl is an ionic compound (B) soap is insoluble in the presence of choride ions (C) the solubility product of NaCl decreases in the presence of soap (D) the solubility product of the soap is exceeded due to the increased concentration of Na+ ions. 3 5 . 16.6 mg of solid silver chromate (molar mass = 332) when put into 500 mL water, silver ion and chromate ion are obtained. On adding more solid, the concentration of ions does not increase. If 100 mg of solid is put into 2 litre of water, then the amount of solid remained undissociated would be- (A) 33.6 mg (B) 3.36 mg (C) 66.4 mg (D) 6.64 mg 3 6 . In which of the following solvents will AgBr has highest solubility- (A) 10–3 M NaBr (B) 10–3 M NH4OH (C) pure water (D) 10–3 M HBr 3 7 . In the system CaF2(s) Ca+2 (aq) + 2F– increasing the concentration of Ca2+ ions 4 times will cause the equilibrium concentration of F– ions to change to .... times the initial value. (A) 4 (B) 1/2 (C) 2 (D) 1/4
3 8 . The solubility of Fe(OH)3 would be maximum in- (A) 0.1 M NaOH (B) 0.1 M HCl (C) 0.1 M KOH (D) 0.1 M H2SO4 3 9 . Arrange in increasing order of solubility of AgBr in solutions given : (i) 0.1 M NH3 (ii) 0.1 M AgNO3 (iii) 0.2 M NaBr (iv) pure water (A) (iii) < (ii) < (iv) < (i) (B) (iii) < (ii) < (i) < (iv) (C) (iii) < (ii) = (i) < (iv) (D) (ii) < (iii) < (iv) < (i) 4 0 . The solubility product of BaCrO4 is 2.4 × 10–10 M2. The maximum concentration of Ba(NO3)2 possible without precipitation in a 6 × 10–4 M K2CrO4 solution is- (A) 4 × 10–7 M (B) 1.2 × 1010 M (C) 6 × 10–4 M (D) 3 × 10–4M 4 1 . At 25 °C, the solubility product values of AgCl and AgCNS are 1.7 × 10–10 and 1.0 × 10–12 respectively. When water is saturated with both solids, calculate the ratio [Cl–]/[CNS–] and also [Ag+] in the solution. (A) 1.3 × 102, 1.7 × 10–5 M (B) 1.7 × 102, 1.308 × 10–5 M (C) 1.3 × 104, 1.308 × 10–4 M (D) 1.7 × 103, 1.67 × 10–6 M 4 2 . When pure water is saturated with CaCO3 and CaC2O4, the concentration of calcium ion in the solution under equilibrium is 8.426 × 10–5 M. If the ratio of the solubility product of CaCO3 to that of CaC2O4 is 2.087, what is the solubility product of CaCO3 in pure water ? (A) 4.80 × 10–8 (B) 9.60 × 10–9 (C) 9.60 × 10–8 (D) 4.80 × 10–9 4 3 . The solubility of Ag2CO3 in water at 25 °C is 1 × 10–4 mole/litre. What is its solubility in 0.1 M Na2CO3 2– solution ? Assume no hydrolysis of CO 3 ion. (A) 6.323 × 10–6 mole/litre (B) 4.74 × 10–5 mole/litre (C) 3.16 × 10–6 mole/litre (D) 5.51 × 10–5 mole/litre 4 4 . The solubility of calcium phosphate in water is x mol L–1 at 25 °C. Its solubility product is equal to- (A) 108 x2 (B) 36 x3 (C) 36 x5 (D) 108 x5 4 5 . The solubility product of AgCl is 1.8 × 10–10. Precipitation of AgCl will occur only when equal volumes of solutions of- (A) 10–4 M Ag+ and 10–4 M Cl– are mixed (B) 10–7 M Ag+ and 10–7 M Cl– are mixed (C) 10–5 M Ag+ and 10–5 M Cl– are mixed (D) 10–10 M Ag+ and 10–10 M Cl– are mixed 4 6 . The solubility of CaF2 (Ksp = 3.4 × 10–11) in 0.1 M solution of NaF would be- (A) 3.4 × 10–12 M (B) 3.4 × 10–10 M (C) 3.4 × 10–9 M (D) 3.4 × 10–13 M 4 7 . The precipitate of CaF2(Ksp = 1.7 × 10–10) is obtained when equal volumes of the following are mixed. (A) 10–4 M Ca2+ + 10–4 M F– (B) 10–2 M Ca2+ + 10–3 M F– (C) 10–5 M Ca2+ + 10–3 M F– (D) 10–3 M ca2+ + 10–5 M F– 4 8 . Let the solubilities of AgCl in H2O, 0.01 M CaCl2, 0.01 M NaCl & 0.05 M AgNO3 be S1, S2, S3 & S4 respectively what is the correct relationship between these quantities. Neglect any complexation. (A) S1 > S2 > S3 > S4 (B) S1 > S2 = S3 > S4 (C) S1 > S3 > S2 > S4 (D) S4 > S2 > S3 > S1 4 9 . The solubility product Mg(OH)2 in water at 25 °C is 8.9 × 10–13 (mole dm–3)3 while that of Al(OH)3 is 5 × 10–33 (mol dm–3)4. If S1 and S2 are the solubilities of Mg(OH)2 and Al(OH)3 in water in mol dm–3 at 25 °C, what is the order of magnitude of the ratio, S1/S2 ? (A) 105 (B) 104 (C) 106 (D) 103 5 0 . When HCl gas is passed through a saturated solution of common salt, pure NaCl is precipitated because- (A) HCl is highly ionised in solution (B) HCl is highly soluble in water (C) the solubility product of NaCl is lowered by HCl (D) the ionic product of [Na+] [Cl–] exceeds the solubility product of NaCl
5 1 . A certain indicator (an organic dye) has pKa = 5. For which of the following titrations may it be suitable. (A) acetic acid against NaOH (B) aniline hydrochloride against NaOH (C) sodium carbonate against HCl (D) barium hydroxide against oxalic acid 5 2 . The pH indicators are- (A) salts of strong acids & strong bases (B) salts of weak acids & weak bases (C) either weak acids or weak bases (D) either strong acids or strong bases 5 3 . What fraction of an indicator Hln is in the basic form at a pH of 6 if pKa of the indicator is 5 ? 1 1 10 1 (A) (B) (C) (D) 2 11 11 10 5 4 . An acid-base indicator which is a weak acid has a pKa value = 5.5. At what concentration ratio of sodium acetate to acetic acid would the indicator show a colour half-way between those of its acid and conjugate base forms ? pKa of acetic acid = 4.75 (A) 4.93 : 1 (B) 6.3 : 1 (C) 5.62 : 1 (D) 2.37 : 1 CHECK YOUR GRASP ANSWER KEY EXERCISE -1 Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans. D D A A B B B C B C C D B D C Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans. A A C A B A B D A C B D D D A Que. 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Ans. B A D D A B B D A A B D C D A Que. 46 47 48 49 50 51 52 53 54 Ans. C B C B D C C C C
EXERCISE–02 BRAIN TEASERS SELECT THE CORRECT ALTERNATIVES (ONE OR MORE THEN ONE CORRECT ANSWERS) 1 . The conjugate acid of NH2– is- (A) NH3 (B) NH2OH (C) NH4+ (D) N2H4 2 . Out of the following, amphiprotic species are (IV) HCO3– (D) All (I) HPO32– (II) OH– (iii) H2PO4– (A) I, III, IV (B) I and III (C) III and IV 3 . pH of an aqueous solution of NaCl at 85 °C should be- (A) 7 (B) > 7 (C) < 7 (D) 0 4 . 1 CC of 0.1 N HCl is added to 99 CC solution of NaCl. The pH of the resulting solution will be- (A) 7 (B) 3 (C) 4 (D) 1 MM 5 . 10 mL of 200 H2SO4 is mixed with 40 mL of 200 H2SO4. The pH of the resulting solution is- (A) 1 (B) 2 (C) 2.3 (D) none of these 6 . If pKb for fluoride ion at 25 °C is 10.83, the ionization constant of hydrofluoric acid in water at this temperature is- (A) 1.74 × 10–5 (B) 3.52 × 10–3 (C) 6.75 × 10–4 (D) 5.38 × 10–2 7 . If K1 & K2 be first and second ionisation constant of H3PO4 and K1 >> K2 which is incorrect- (A) [H+] = [H2PO4–] (B) [H+] = K1[H3PO4 ] (C) K2 = [H P O – 2] (D) [H+] = 3[PO43–] 4 8 . The degree of hydrolysis of a salt of weak acid and weak base in it's 0.1 M solution is found to be 50%. If the molarity of the solution is 0.2 M, the percentage hydrolysis of the salt should be- (A) 100 % (B) 50 % (C) 25 % (D) none of these 9 . What is the percentage hydrolysis of NaCN in N/80 solution when the dissociation constant for HCN is 1.3 × 10–9 and Kw = 1.0 × 10–14 (A) 2.48 (B) 5.26 (C) 8.2 (D) 9.6 1 0 . pH of 0.01 M (NH4)2SO4 and 0.02 M NH4OH buffer solution (pKa of NH4+ = 9.26) is- (A) 9.26 (B) 4.74 (C) 4.74 + log 2 (D) none 1 1 . The range of most suitable indicator which should be used for titration of X–Na+ (0.1 M, 10 mL) with 0.1 M HCl should be (Given : kb(X) = 10–6) (A) 2 – 3 (B) 3 – 5 (C) 6 – 8 (D) 8-10 1 2 . When NO2 is bubbled into water, If dispropor tionates completely into HNO2 and HNO3. 2NO2 + H2O() HNO2(aq.) + HNO3(aq.) The concentration of NO2– in a solution prepared by dissolving 0.05 mole of NO2 gas in 1 litre H2O is {Ka(HNO2) = 5 × 10–4} (A) ~ 5 × 10–4 (B) ~ 4.8 × 10–5 (C) ~ 4.8 × 10–3 (D) ~ 2.55 × 10–2 1 3 . If Ksp for HgSO4 is 6.4 × 10–5, then solubility of this substance in mole per m3 is- (A) 8 × 10–3 (B) 6.4 × 10–5 (C) 8 × 10–6 (D) none of these 1 4 . Which of the following is most soluble in water ? (A) MnS(Ksp = 8 × 10–37) (B) ZnS(Ksp = 7 × 10–16) (C) Bi2S3(Ksp = 1 × 10–72) (D) Ag3(PO4) (Ksp = 1.8 × 10–8)
1 5 . How many moles NH3 must be added to 2.0 litre of 0.80 M AgNO3 in order to reduce the Ag+ concentration to 5 × 10–8 M. Kf of [Ag(NH3)2+] = 108 (A) 0.4 (B) 2 (C) 3.52 (D) 4 1 6 . The solubility product of BaF2 has the value, 1.7 × 10–4. If V1 mL of BaCl2 Solution (10–1 M) and V2 mL of NaF solution (10–2 M) are mixed, what is the ratio V1 : V2 so that a precipitate may be obtained ? (A) 1 : 1 (B) 2 : 1 (C) 1 : 2 (D) precipitate cannot obtained for any possible ratio 1 7 . At 18 °C, the solubility of CdS in water is 6.33 × 10–15 M. What is the concentration of Cd+ ion in a solution of pH = 1 saturated with H2S gas, in which concentration of H2S = 0.1 M ? The product of the first and second ionization constants of H2S is 1.1 × 10–22 at this temperature. (A) 6.343 × 10–8 M (B) 4. 368 × 10–8 M (C) 4.368 × 10–9 M (D) 3.643 × 10–8 M 1 8 . 100 mL of 0.02 M benzoic acid (pKa = 4.2) is titrated using 0.02 M NaOH. pH after 50 mL and 100 mL of NaOH have been added are- (A) 3.50,7 (B) 4.2, 7 (C) 4.2, 8.1 (D) 4.2, 8.25 1 9 . What is the pH of solution made by adding 3.9 g NaNH2 into water to make a 500 mL solution Kb(NH3) = 2 × 10–5 [Na = 23, N = 14, H = 1] (A) 13.3 (B) 0.7 (C) 5.3 (D) 13.7 2 0 . 10.2 g of acetic anhydride was added to 989.8 g of water to make a solution with a density of 1g/mL. If the ka of acetic acid is 2 × 10–5, the pH of the solution would be [C = 12, H = 1, O = 16] (A) 2.7 (B) 3.7 (C) 4.7 (D) 5.7 2 1 . A well is dug in a bed of rock containing fluorspar (CaF2). If the well contains 20000 L of water, what is the amount of F– in it ? Ksp = 4 × 10–11 (A) 4.3 mol (B) 6.8 mol (C) 8.6 mol (D) 13.6 mol 2 2 . If HA + NaOH NaA + H2O H = – 12 kcal and HB + NaOH NaB + H2O H = –11 kcal then equimolar solution of which acid has higher pH- (A) HA (B) HB (C) both have same pH (D) information insufficient 2 3 . Aniline behaves as a weak base. When 0.1 M, 50 mL solution of aniline was mixed with 0.1 M, 25 mL solution of HCl the pH of resulting solution was 8. Then the pH of 0.01 M solution of aniliniumchloride will be (Kw = 10–14) (A) 6 (B) 6.5 (C) 5 (D) 5.5 2 4 . pH of a mixture of 1 M benzoic acid (pKa = 4.20) and 1M C6H5COONa is 4.5, what is the volume of benzoic acid required to prepare a 300 mL buffer [log 2 = 0.3] ? (A) 200 mL (B) 150 mL (C) 100 mL (D) 50 mL 2 5 . What is the difference in pH for 1/3 and 2/3 stages of neutralisation of 0.1 M CH3COOH with 0.1 M NaOH. (A) – 2 log 3 (B) 2log(1/4) (C) 2log(2/3) (D) – 2 log 2 2 6 . An acid HA(ka = 10–5) reacts with NaOH at 298 K. What would be the value of the rate constant of the reverse reaction at the same temperature if the rate constant of the forward reaction is 10–11 mol–1 L sec–1 ? (A) 10–9 (B) 109 (C) 10–5 (D) 10–20
2 7 . The pH of 1.0 M NaHSO4 solution will be (given that K1 and K2 for H2SO4 equal to and 10–2 respectively)- (A) nearly 1.0 (B) between 2 and 3 (C) between 1.2 and 1.8 (D) between 3 and 4 2 8 . 0.1 millimole of CdSO4 are present in 10 mL acid solution of 0.08 N HCl. Now H2S is passed to precipitate all the Cd2+ ions. The pH of the solution after filtering off precipitate, boiling off H2S and making the solution 100 mL by adding H2O is- (A) 2 (B) 4 (C) 6 (D) 8 2 9 . Zn salt is mixed with (NH4)2 S of molarity 0.021 M. The amount of Zn2+ remains unprecipitated in 12 mL of this solution would be (Given : KSP ZnS = 4.51 × 10–24) (A) 1.677 × 10–22 g (B) 1.767 × 10–22 g (C) 2.01 × 10–23 g (D) none of these 3 0 . The self ionisation constant for pure formic acid, K = [HCOOH2+] [HCOO–] has been estimated as 10–6 at room temperature. The density of formic acid is 1.22 g/cm3. The percentage of formic acid molecules in pure formic acid that are concerted to formate ion would be- (A) 0.002 % (B) 0.004 % (C) 0.006 % (D) 0.008 % BRAIN TEASERS ANSWER KEY EXERCISE -2 Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans. A C C B B C D B A A B A D D D Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans. D D C A A C B C C D D AA AB
EXERCISE–03 MISCELLANEOUS TYPE QUESTIONS TRUE / FALSE 1 . When a solution of a weak monoprotic acid is titrated against a strong base, at half-neutralization point, 1 pH = 2 pKa 2 . A solution of sodium acetate and ammonium acetate can act as a buffer. 3 . If the solubility of the salt Li3Na3(AlF6)2 is x, then its solubility product would be 2916 x8. 4 . A buffer has maximum buffer capacity when the ratio of salt to acid is 10. 5 . In the presence of a common ion (incapable of froming complex ion), the solubility of salt decreases. 6 . The ionic product of water changes if a few drops of acid or base are added to it. 7 . When equilibrium is attained, the concentration of each of the reactants & products become equal. 8 . The reaction, HCN + OH– CN– + H2O is displaced to the right indicating that the acid strength of HCN is greater than water & the base strength of CN– is greater than that of OH–. 9 . The hydroxyl ion is hydrated to give several ionic species like H O –2, H O –3 and H O –4. 22 33 44 1 0 . Ostwald's dilution formula is applicable to weak as well as strong electrolytes. 1 1 . CO2 is a Lewis base 1 2 . Solution whether neutral, acidic or basic contain both H+ & OH– ions. 1 3 . The ionic product of a saturated solution is equal to solubility product constant of its solute. 1 4 . A Lewis base is a substance which can donate a pair of electrons ? 1 5 . If ionic product is less than k , no precipitation will occur. sp 1 6 . A buffer has definite pH value which changes on keeping it or on diluting it. 1 7 . A salt of strong acid with a strong base does not undergo hydrolysis 1 8 . HCl does not act as an acid in benzene 1 9 . Water acts as a base when ammonia is dissolved in it. 2 0 . In the reaction, SnCl4 + 2Cl– [SnCl6]2–, SnCl4 is a Lewis acid. 2 1 . The strength of an oxy acid increases with increase in the EN value of central atom. 2 2 . In aqueous solution the hydronium ion is further hydrated to give species like H5O2+, H7O3+ and H9O4+ FILL IN THE BLANKS 1 . In a mixture of weak acid and its salt, the ratio of concentration of salt to acid is increased ten fold. The pH of the solution would ....... by ....... unit. 2 . The solubility of CH3COOAg in water considering hydrolysis of CH3COO– ions would be ....... than that ignoring the hydrolysis. 3 . From an equimolar solution of Cl– and Br– ions, the addition of Ag+ will selectively precipitates ....... (Ksp of AgCl & AgBr are 1 × 10–10 & 1 × 10–13 respectively). 4 . The solubility of AgCl in NH is ...... than the solubility in pure water because of complex ion, [Ag(NH ) ]+ 3 32 formation. 5 . The hydrolytic constant Kh for the hydrolytic equilibrium – H2P O 4 + H2O H3PO4 + OH– is 1.4 × 10–12 The value of ionization constant for the H3PO4 + H2O H2PO4– + H3O+ is ...................... . 6 . Given the equilibrium constants Cl– + HgCl+ HgCl2 ; K1 = 3 × 106 HgCl2 + Cl– HgCl3– ; K2 = 8.9 The equilibrium constants for the dispropotionation equilibrium. 2HgCl2 HgCl+ + Hg Cl – is- 3
7 . If the salts M2X, QY2 and PZ3 have same solubilities (<<< 1), their Ksp values are related as ........... 8 . K for an acid HA is 1 × 10–6. K for A– would be ....... ab 9 . An aqueous solution of K2SO4 has pH nearly equal to ....... 1 0 . The pH of a solution which is 0.1 M sodium acetate and 0.01 M acetic acid (pKa = 4.74) would be .......... 1 1 . The conjugative acid of sulphate (SO 2–) is .......... 4 1 2 . The value of Kw ......... with increase in temperature. 1 3 . AgCl is ......... soluble in aqueous sodium chloride solution than in pure water. 1 4 . The buffer HCOOH/HCOONa will have pH ......... than 7. 1 5 . In the reaction I2 + I– I3–, I2 acts as ......... 1 6 . An equimolar solution of NaNO2 and HNO2 can act as a ......... solution. 1 7 . Larger the value of pK , ............. is the acid a 1 8 . Between Na+ & Ag+ ion, ........... is a stronger Lewis acid. 1 9 . Salt of strong acids and weak base undergo ........... hydrolysis 2 0 . For salts of weak acid with weak bases, degree of hydrolysis is ....... of concentration of the salt in solution. 2 1 . The solubility of KAl (SO4)2 in terms of its solubility product is ........ 2 2 . The dissociation constant of NH4OH is 1.8 × 10–5. The hydrolysis constant of NH4+ ions at 25 °C would be ........ 2 3 . solution of CuSO is ........ due to the hydrolysis of ........ ions 4 2 4 . The colour of unionized form of phenolphthalein is ........ whereas that of ionized form is ......... 2 5 . In general, in aqueous solution pH + pOH = ........ at all temperatures. 2 6 . The ionization constant of water is related to ionic product by the expression ............. 2 7 . The smaller the value of Ka of a weak acid, ......... is the hydrolysis constant of its conjugate base. MATCH THE COLUMN 1 . Match the effect of addition of 1 M NaOH to 100 mL 1 M CH COOH (in Column I) with pH (in Column II) : 3 Column-I Column-II (A) 25 mL of NaOH (p) pK (B) 50 mL of NaOH a (C) 75 mL of NaOH (q) pK + log 3 a (r) pK – log 3 a (D) 100 mL of NaOH 1 (s) [pK + pK – log 2] 2w a 2 . When we titrate sodium carbonate solution (in beaker) with hydrochloric acid. Column-I Column-II (A) At the start of titration (B) Before the first equivalent point (p) Buffer solution of HCO – and CO 2– (C) At the first equivalent point 33 (q) Buffer solution of H CO and HCO – 23 3 (r) Amphiprotic anion, (D) Between the first and second equivalent pH = 1/2(pK + pK ) points a1 a2 (s) Hydrolysis of CO 2– 3
ASSERTION & REASON These questions contains, Statement I (assertion) and Statement II (reason). (A) Statement-I is true, Statement-II is true ; Statement-II is correct explanation for Statement-I. (B) Statement-I is true, Statement-II is true ; Statement-II is NOT a correct explanation for statement-I (C) Statement-I is true, Statement-II is false (D) Statement-I is false, Statement-II is true 1 . Statement-I : On dilution of a concentrated solution of CH3COOH, the concentration of [H+] decreases Because Statement-II : Because increase in the volume is more than the increase in degree of ionisation 2 . Statement-I : pH of boiling water is less than the water at 4 °C Because Statement-II : Because density of water is maximum at 4 °C 3 . Statement-I : Solubility of BaSO in 0.1 M Na SO is 10–9 M hence its K is 10–18 4 24 sp Because Statement-II : Because for BaSO K = (s)2 4 sp 4 . Statement-I : Aqueous solution of CH3COONH4 is found to be neutral Because Statement-II : because this salt does not undergo hydrolysis 5 . Statement-I : An aqueous solution of HCl is a much better conductor of electricity than an aqueous solution of CH3COOH of the same concentration. Because Statement-II : The freezing point depression and the boiling point elevation of weak electrolytes are significantly less than for strong electrolytes of the same concentration. 6 . Statement-I : CH NH + CH NH is acid base conjugate pair. 33 32 Because Statement-II : H O+, OH– is acid base conjugate pair. 3 7 . Statement-I : The equilibrium constant for the reaction, HONO(aq.) + CN–(aq) HCN (aq.) + ONO–(aq.) is 1.1 × 106 Because Statement-II : This shows that CN– is stronger base than ONO– COMPREHENSION BASED QUESTIONS Comprehension # 1 The importance of pH maintenance in Blood Maintenance of the pH in blood and in intracellular fluids is absolutely crucial to the processes that occur in living organisms. This primarily because the functioning of enzymes-catalysts for these processes - is sharply pH dependent. The normal pH value of blood plasma is 7.4. Severe illness or death can result from sustained variations of a few tenths of pH unit. Among the factors that lead to a condition of acidosis, in which there is decreases in the pH of blood are heart failure, kidney failure diabetes mellitus, persistent diarrhoea or a long term high protein diet. A temporary condition acidosis may result from prolonged, intensive exercise. Alkalosis, which causes increase in pH of blood, may occur as a result of severe vomiting overbreathing or exposure to high altitudes.
Several factors are involved in the control of the pH of blood. A particularly important one is the ratio of dissolved HCO – to H CO . CO (g) is moderately soluble in water and in aqueous solution reacts only 3 23 2 to a limited extent to produce H2CO3. CO2 + H2O H2CO3 (aq) H2CO3 + H2O H C O – + H3O+, pK a1 6.11 3 pK a2 10.25 H C O – + H2O C O 2– + H3O+ ; 3 3 In the H2CO3, HCO3– buffer system we deal only with the first ionisation step ( K a1 ) : H2CO3 is weak acid and HCO – is the conjugate base (salt). CO2 enters the blood from tissues as the by - product of 3 metabolic reaction. In lungs, CO2 (g) is exchanged for O2 (g), which is transported throughout the body by the blood. 1 . The pH of blood stream is maintained by a proper balance of H2CO3 and NaHCO3 concentration. What volume of 5 M NaHCO3 solution should be mixed with a 10 mL sample of blood which is 2 M in H2CO3 in order to maintain its pH? : (A) 40 mL (B) 38 mL (C) 50 mL (D) 78 mL 2 . Important diagnostic analysis in the blood is : (A) [H2PO4–]/[HPO4–] (B) [HCO3–]/[CO2] (C) [CO32–]/[HCO32–] (D) [PO43–]/[HPO42–] 3 . Following reaction occurs in the body : CO2 + H2O H2CO3 H+ + H C O – 3 If CO2 escapes from the system : (A) pH will decreases (B) pH will increases (C) [H2CO3] remains unchanged (D) forward reaction is promoted Comprehension # 2 Phosphoric acid is of great importance in fertilizer production. Besides, phosphoric acid and its various salts have a number of application in metal treatment, food, detergent and toothpaste industries. pK a1 2.12, pK a2 7.21, pK a3 12.32 Small quantities of phosphoric acid are extensively used to impart the sour or tart taste to many soft drinks such as colas and roots beers, in which a density of 1.00 g mL–1 contains 0.05% by weight of phosphoric acid. Phosphoric acid is used as a fertiliser for agriculture and an aqueous soil digesting. 1.00 × 10–3 M phosphoric acid is found to have pH = 7. Zinc is an essential micronutrient for plant growth. Plants can absorb zinc in water soluble from only. In the given soil, zinc phosphate is only the source of zinc and phosphate ions, Ksp (zinc phosphate) = 9.1 × 10–33. 1 . Phosphoric acid is a tribasic acid with three-step ionisation constants. Thus, its structure is : H OH OH H (A) H P O H (B) H P O H (C) H O P O H (D) H O P H OO O OO 2 . What is the pH of the cola assuming that the acidity of the cola arises only from phosphoric acid and second and third ionisation constants are of no importance ? (A) 2.2 (B) 3.3 (C) 4.4 (D) 1.8
3 . Molar concentration of phosphate ion in the soil with pH 7 is : (A) 1.2 × 10–4 M (B) 2.2 × 10–4 M (C) 1 × 10–3 M (D) 1.1 × 10–10 M 4 . Concentration of [Zn2+] in the soil is : (A) 9.1 × 10–5 M (B) 5.7 × 10–9 M (C) 4.0 × 10–10 M (D) 3.0 × 10–6 M MISCELLANEOUS TYPE QUESTION ANSWER KEY EXERCISE -3 True / False 2. F 3. T 4. F 1. F 6. F 7. F 8. F 5. T 10. F 11. F 12. T 9. F 14. T 15. T 16. F 13. T 18. T 19. F 20. T 17. T 22. T 21. T 3 . Br– ion 4 . Greater Fill in the Blanks 1 . Increase, one 2. Greater 5 . 7.14 × 10–3 6 . 3 × 10–6 7 . M2X = QY2 > PZ3 8 . 10–8 9. 7 10 . 5.74 1 3 . Less 1 4 . Less 1 1 . HSO4– 1 2 . Increases 1 5 . Lewis acid 1 6 . Buffer 1 7 . Weaker 18. Ag+ 1 9 . Cationic 2 0 . Independent 2 1 . (Ksp/4)1/4 2 2 . 5.556 × 10–10 2 3 . Acidic, Cu++ 2 4 . Colourless, Pink 2 5 . pKw (not 14 !!) 2 6 . kW = k[H2O] 2 7 . Greater Match the Column 1. A - (r), B - (p), C - (q), D - (s) 2. A - (s), B - (p), C - (r), D - (q) Assertion - Reason Questions 1. A 2. B 3. D 4. C 5. B 6. C 7. A Comprehension Based Questions Comprehension #1 : 1. D 2. B 3. B 4. B Comprehension #2 : 1. C 2. A 3. B
EXERCISE–04 [A] CONCEPTUAL SUBJECTIVE EXERCISE 1 . Calculate (i) Ka for H2O (Kw = 10–14) (ii) Kb for B(OH)4–, Ka(B(OH)3) = 6 × 10–10 (iii) K for HCN, K (CN–) = 2.5 × 10–5 ab 1 2 . Calculate the ratio of degree of dissociation (2/1) when 1 M acetic acid solution is diluted to 100 times. (Given Ka = 1.8 × 10–5) 3 . Calculate the ratio of degree of dissociation of acetic acid and hydrocyanic acid (HCN) in 1 M their respective solution of acids (Given Ka(CH3COOH) = 1.8 × 10–5 ; K a(HCN) = 6.2 × 10–10] 4 . Calculate : (a) Ka for a monobasic acid whose 0.10 M solution has pH of 4.50 (b) K for a monoacidic base whose 0.1 M solution has a pH of 10.50 b 5 . Calculate pH of following solution : (a) 0.1 M HCl (b) 0.1 M H2SO4 (50 mL) + 0.4 M HCl 50 (mL) (d) 0.1 M NH4OH (Kb = 1.8 × 10–5) (c) 0.1 M CH3COOH (Ka = 1.8 × 10–5) (f) 10–10 M NaOH (e) 10–8 M HCl (g) 10–6 M CH3COOH (h) 10–8 M CH3COOH (i) 0.1 M HA + 0.1 M HB [Ka(HA) = 2 × 10–5 ; Ka(HB) = 4 × 10–5] (j) Decimolar solution of Baryta (Ba(OH)2), diluted 100 times. (k) 10–3 mole of KOH dissolved in 100 L of water. (l) 0.5 M HCl (25 mL) + 0.5 M NaOH (10 mL) + 40 mL H2O (m) equal volume of HCl solution (PH = 4) + 0.0019 N HCl solution 6 . The value of K at the physiological temperature (37° C) is 2.56 × 10–14. What is the pH at the neutral w point of water at this temperature, where there are equal number of H+ and OH– ? 7 . Calculate the number of H+ present in one mL of solution whose pH is 13 8 . Calculate change in concentration of H+ ion in one litre of water, when temperature changes from 298 K to 310 K. Given Kw(298) = 10–14, Kw(310) = 2.56 × 10–14. 9 . (i) K for H O is 9.62 × 10–14 at 60 °C. What is pH of water at 60 °C. w2 (ii) What is the nature of solution at 60°C whose. (a) pH = 6.7 (b) pH = 6.35 1 0 . The pH of aqueous solution of ammonia is 11.5. Find molarity of solution. K (NH OH) = 1.8 × 10–5. b4 1 1 . The solution of weak monoprotic acid which is 0.01 M has pH = 3. Calculate Ka of weak acid. 1 2 . Boric acid is a weak monoprotic acid. It ionizes in water as B(OH) + H O B(OH) – + H+ : K = 5.9 × 10–10 32 4 a Calculate pH of 0.3 M boric acid. 1 3 . Calculate [H+] and [CHCl2COO–] in a solution that is 0.01 M in HCl and 0.01 M in CHCl2COOH. Take (Ka = 2.55 × 10–2). 1 4 . Calculate [H+], [CH COO–] and [C H O –] in a solution that is 0.02 M in acetic acid and 0.01 M in benzoic 3 752 acid. K (acetic) = 1.8 × 10–5, K (benzoic) = 6.4 × 10–5. aa 1 5 . At 25 °C, the dissociation constant of HCN and HF are 4 × 10–10 and 6.7 × 10–4. Calculate the pH of a mixture of 0.1 M HF and 0.1 M HCN.
POLYPROTIC ACIDS & BASES 1 6 . Determine the [S2–] in a saturated (0.1 M) H2S solution to which enough HCl has been added to produce a [H+] of 2 × 10–4. K1 = 10–7, K2 = 10–14 1 7 . Calculate [H+], [H2PO4–], [HPO42–] and [PO43–] in a 0.01 M solution of H3PO4. Take K1 = 7.225 × 10–3, K2 = 6.8 × 10–8, K3 = 4.5 × 10–13. 18. Calculate the pH of a 0.1 M solution of H2NCH2CH2NH2 ; ethylenediamine (en). Determine the en H 2+ 2 concentration in the solution. K b1 and K b2 values of ethylenediamine are 8.5 × 10–5 and 7.1 × 10–8 respectively. 19. What are the concentration of H+, HSO4– , S O –2 & H2SO4 in a 0.20 M solution of sulphuric acid ? 4 Given : H2SO4 H+ + HSO4– ; strong HSO4– H+ + S O 2– ; K2 = 1.3 × 10–2 M 4 BUFFER SOLUTION 2 0 . Determine [OH–] of a 0.050 M solution of ammonia to which has been added sufficient NH4Cl to make the total [NH4+] equal to 0.100. [ K b(NH3 ) = 1.8 × 10–5] 2 1 . Calculate the pH of a solution prepared by mixing 50.0 mL of 0.200 M HC H O and 50.0 mL of 0.100 232 M NaOH. [ Ka(CH3COOH) = 1.8 × 10–5] 2 2 . A buffer of pH 9.26 is made by dissolving x moles of ammonium sulphate and 0.1 mole of ammonia into 100 mL solution. If pK of ammonia is 4.74, calculate value of x. b 2 3 . 50 mL of 0.1 M NaOH is added to 75 mL of 0.1 M NH4Cl to make a basic buffer. If pKa of NH4+ is 9.26, salculate pH. 2 4 . (a) Determine the pH of a 0.2 M solution of pyridine C5H5N. Kb = 1.5 × 10–9 (b) Predict the effect of addition of pyridinium ion C H NH+ on the position of the equilibrium. Will the 55 pH be raised or lowered ? (c) Calculate the pH of 1.0 L of 0.10 M pyridine solution to which 0.3 mol of pyridinium chloride C5H5NH+Cl, has been added, assuming no change in volume. 2 5 . A buffer solution was prepared by dissolving 0.02 mol propionic acid & 0.015 mol sodium propionate in enough water to make 1.00 L of solution. (Ka for propionic acid is 1.34 × 10–5) (a) What is the pH of the buffer ? (b) What would be the pH if 1.0 × 10–5 mol HCl were added to 10 mL of the buffer ? (c) What would be the pH if 1.0 × 10–5 mol NaOH were added to 10 mL of the buffer. (d) Also report the percent change in pH of original buffer in case (b) and (c) 2 6 . A solution was made up of 0.01 M in chloroacetic acid ClCH2COOH and also 0.002 M in sodium chloracetate ClCH2COONa. What is [H+] in the solution? Ka = 1.5 × 10–3. INDICATORS 2 7 . A certain solution has a hydrogen ion concentration 4 × 10–3 M. For the indicator thymol blue, pH is 2.0 when half the indicator is in unionised from. Find the % of indicator in unionised form in the solution with [H+] = 4 × 10–3 M. 2 8 . Bromophenol blue is an indicator with a Ka value of 6 × 10–5. What % of this indicator is in its basic form at a pH of 5 ? 2 9 . An acid base indicator has a Ka of 3 × 10–5. The acid form of the indicator is red & the basic form is blue. By how much must the pH change in order to change the indicator form 75% red to 75% blue ? H Y D R O LY S I S 3 0 . What is the OH– concentration of a 0.08 M solution of CH3COONa. [Ka(CH3COOH) = 1.8 × 10–5] 3 1 . Calculate the pH of a 2.0 M solution of NH4Cl.[Kb(NH3) = 1.8 × 10–5]
3 2 . 0.25 M solution of pyridinium chloride C5H6N+Cl– was found to have a pH of 2.699. What is Kb for pyridine, C5H5N ? 3 3 . Calculate the extent of hydrolysis & the pH of 0.02 M CH3COONH4 [K (NH ) = 1.8 × 10–5, K (CH COOH) = 1.8 × 10–5] b3 a3 3 4 . Calculate the percent hydrolysis in a 0.06 M solution of KCN. [Ka(HCN) = 6 × 10–10] 3 5 . Calculate the extent of hydrolysis of 0.005 M K2CrO4. [K2 = 3.1 × 10–7 for H2CrO4] (It is essentially strong for first ionization). 3 6 . A 0.010 M solution of PuO2(NO3)2 was found to have a pH of 4.0. What is the hydrolysis constant kh for PuO 2 , and what is Kb for PUO2OH+ ? 2 3 7 . Calculate the pH of 1.0 × 10–3 M sodium phenolate, NaOC6H5 Ka for HOC6H5 is 1.05 × 10–10 . 3 8 . What is the pH of 0.1 M NaHCO3 ? K1 = 4.5 × 10–7, K2 = 4.5 × 10–11 for carbonic acids. 3 9 . Calculate pH of 0.05 M potassium hydrogen phthalate, KHC H O . 844 H2C8H4O4 + H2O H3O+ + H C 8H 4O – pK1 = 2.94 4 H C 8 H 4O – + H2O H3O+ + C8 H4 O24 pK2 = 5.44 4 4 0 . Calculate OH– concentration at the equivalent point when a solution of 0.1 M acetic acid is titrated with a solution of 0.1 M NaOH. Ka for the acid = 1.9 × 10–5. 4 1 . The acid ionization hydrolysis constant of Zn2+ is 1.0 × 10–9 (a) Calculate the pH of a 0.001 M solution of ZnCl2 (b) What is the basic dissociation constant of Zn(OH)+ ? ACID BASE REACTIONS & TITR ATIONS 4 2 . Calculate the hydronium ion concentration and pH at the equivalence point in the reaction of 22.0 mL of 0.10 M acetic acid, CH3COOH, with 22.0 mL of 0.10 M NaOH. 4 3 . Calculate the hydronium ion concentration and the pH at the equivalence point in a titration of 50.0 mL of 0.40 M NH with 0.40 M HCl. 3 4 4 . In the titration of a solution of a weak acid HX with NaOH, the pH is 5.8 after 10.0 mL of NaOH solution has been added and 6.402 after 20.0 mL of NaOH has been added. What is the ionization constant of HX ? 4 5 . The equivalent point in a titration of 40.0 mL of a solution of a weak monoprotic acid occurs when 35.0 mL of a 0.10 M NaOH solution has been added. The pH of the solution is 5.75 after the addition of 20.0 mL of NaOH solution. What is the dissociation constant of the acid ? 4 6 . A weak base (50.0 mL) was titrated with 0.1 M HCl. The pH of the solution after the addition of acid 10.0 mL and 25.0 mL were found to be 9.84 and 9.24, respectively. Calculate K of the base and b pH at the equivalence point. 4 7 . A weak acid (50.0 mL) was titrated with 0.1 M NaOH. The pH values when 10.0 mL and 25.0 mL of base have been added are found to be 4.16 and 4.76, respectively. Calculate K of the acid and pH a at the equivalence point. 4 8 . CH COOH (50 mL, 0.1 M) is titrated against 0.1 M NaOH solution. Calculate the pH at the addition 3 of 0 mL, 10 mL, 20 mL, 25 mL, 40 mL, 50 mL of NaOH. K of CH COOH is 2 × 10–5. a3 SOLUBILITY & SOLUBILITY PRODUCT'S 4 9 . The values of Ksp for the slightly soluble salts MX and OX2 are each equal to 4.0 × 10–18. Which salt is more soluble ? Explain your answer fully. 5 0 . The solubility of PbSO4 water is 0.038 g/L. Calculate the solubility product constant of PbSO4. 5 1 . Calculate the solubility of Mg(OH)2 in water. Ksp = 1.2 × 10–11.
5 2 . How many mol CuI(Ksp = 5 × 10–12) will dissolve in 1.0 L of 0.10 M NaI solution ? 5 3 . What is the solubility (in mol/L) of Fe(OH)3 in a solution of pH = 8.0? [Ksp for Fe(OH)3 = 1.0 × 10–36] 5 4 . Calculate the solubility of A2X3 in pure water, assuming that neither kind of ion reacts with water. For A X , [K = 1.1 × 10–23] 23 sp 5 5 . What mass of Pb2+ ion is left in solution when 50.0 mL of 0.20 M Pb(NO ) is added to 50.0 mL of 32 1.5 M NaCl ? [Given Ksp for PbCl2 1.7 × 10–4] 5 6 . A solution has a Mg2+ concentration of 0.0010 mol/L. will Mg(OH)2 precipitate if the OH– concentration of the solution is [Ksp = 1.2 × 10–11] (a) 10–5 mol/L (b) 10–3 mol/L ? 5 7 . Calculate solubility of PbI2(Ksp = 1.4 × 10–8) in water at 25°, which is 90% dissociated. 5 8 . Calculate the Simultaneous solubility of AgSCN and AgBr. Ksp(AgSCN) = 1.1 × 10–12, K (AgBr) = 5 × 10–13. sp 5 9 . Calculate F– in a solution saturated with respect of both MgF and SrF . K (MgF ) = 9.5 × 10–9, 2 2 sp 2 Ksp(SrF2) = 4 × 10–9. COMPLEXATION EQUILIBRIA 6 0 . Assuming no change in volume, calculate the minimum mass of NaCl necessary to dissolve 0.010 mol AgCl in 100 L solution. [K f( A g C l – ) = 3 × 105, Ksp = (AgCl) = 1 × 10–10] 2 61. How much AgBr could dissolve in 1.0 L of 0.40 M NH3 ? Assume that Ag(NH3) + is the only complex 2 formed. [K (Ag(NH ) +) = 1 × 108, K (AgBr) = 5 × 10–13] f 32 sp 6 2 . A solution of 0.1 M Cl–, 0.1 M Br– and 0.1 M I– solid AgNO is gradually added to this solution. Assuming 3 that the addition of AgNO3 does not change the volume. Answer the following : (a) What conc. of Ag+ ions will be required to start precipitation of each of the three ions. (b) Which ion will precipitate first (c) What will be the conc. of this ion when the second ion start precipitating. (d) What will be the conc. of both ions when the third ion start precipitating. Given : Ksp (AgCl) = 1.7 × 10–10, Ksp(AgBr) = 5 × 10–13 Ksp(AgI) = 8.5 × 10–17. 6 3 . The solubility of CaCO3 is 7 mg/litre. Calculate the solubility product of BaCO3 from this information and from the fact that when Na2CO3 is added slowly to a solution containing equimolar concentration of Ca+2 and Ba+2, no precipitate is formed until 90% of Ba+2 has been precipitated as BaCO3. 6 4 . A solution containing 0.10 M Zn2+ and 0.10 M Fe2+ is saturated with H2S. What must be the H+ concentration to separate these ions by selective precipitating ZnS. What is the smallest Zn2+ concentration that can be achieved without precipitating any of Fe2+ as FeS. KspZnS = 1.2 × 10–23, KspFeS = 3.7 × 10–19. [Take : [H S] = 0.1 M and K = 1.1 × 10–7, K = 1 × 10–14] 2 12 6 5 . (a) Will Mg(OH)2 precipitate from a solution that is 0.01 M in MgCl2 and also 0.10 M in NH3. (b) What NH + must maintained to prevent the precipitation of Mg(OH)2 from a solution that is 4 0.010 MgCl2 in 0.1 MNH3 Ksp Mg (OH)2 = 2.5 × 10–11, Kb NH3 = 1.8 × 10–5 6 6 . Calculate the solubi lit y of AgCN in a buffer solution of pH 3. Neglect any complexat ion. Take K (AgCN) = 3.2 × 10–16, K (HCN) = 6.4 × 10–10. sp a 67. Silver ion forms Ag (CN ) – in the presence of excess CN–. How much KCN should be added to 1 litre 2 of a 0.0005 M Ag+ solution in order to reduce [Ag+] to 1 × 10–19 Kb A g (C N ) – = 1 × 10–21. 2
6 8 . How many moles of solid NaOH must be added to 1.0 litre of H2O in order to dissolve 0.10 mole of Zn(OH)2 according to the equation Zn(OH) + 2OH– Zn(OH) 2– 24 KspZn(OH)2 = 4.5 × 10–17, K i ns t Z n ( O H ) 2– = 3.6 × 10–16. 4 CONCEPTUAL SUBJECTIVE EXERCISE ANSWER KEY EXERCISE-4(A) 1 . (i) 1.8 × 10–16, (ii) 1.66 × 10–5, (iii) 4 × 10–10 2 . 1 0 3. 170.4 4 . (a) K = 10–8, (b) K = 10–6 a b 5 . (a) +1, (b) 0.522, (c) 2.87, (d) 11.13 (e) 6.97, (f) 6.996, (g) 6.01, (h) 6.97, (i) 2.61, (j) 11.30 (k) 9 (l) 1, (m) 3 6. 6.795 7 . 6.022 × 107 8 . 0.6 × 10–7 9 . (i) 6.51 ; (ii) (a) Basic, (b) Acidic 10 . 0.556 M 1 1 . 1.11 × 10–4 12. 4.87 1 3 . [H+] = 1.612 × 10–2M, [CHCl2COO–] = 6.126 × 10–3 M 1 4 . [H+] = 10–3M, [CH3COO–] = 3.6 × 10–4 M, [C7H5O2–] = 6.4 × 10–4 M 15. 2.08 1 6 . [S2–] = 2.5 × 10–15 1 7 . [H+] = [H PO –] = 5.623 × 10–3, [HPO –2] = 6.8 × 10–8, [PO 3–] = 5.441 × 10–18 24 44 1 8 . pH = 11.46,[enH 2+] = 7.1 × 10–8 1 9 . 0.2216 M, 0.1884 M, 0.0116 M, 0 2 2 0 . [OH–] = 9.0 × 10–6 21. 4.74 22 . 0.05 mol 23. 9.56 2 4 . (a) pH = 9.239(b) lowered (c) pH = 4.699 2 5 . (a) 4.7525 (b) 4.697 (c) 4.798 (d) 1.134% on acid addition 0.96 % on base addition. 2 6 . [H+] = 2.5 × 10–3 2 7 . [HIn] = 28.57 % 28 . 85.71% 29 . pH=0.954 3 0 . [OH–] = 6.664×10–6 3 1 . pH = 4.4773 2 . Kb = 6.25 × 10–10 33 . 0.56%, pH=7 34 . 1.667 % 35. 0.26% 3 6 . 10–6 ; 10–8 37 . pH = 10.43 38. 8.34 39. 4.19 4 0 . 5.12×10–6 M 4 1 . (a) 6 (b) 1 × 10–5 42. 8.71 43. 4.98 4 4 . 7.94 × 10–7 4 5 . Ka = 2.37 × 10–6 46. 1.73 × 10–5, 5.27 5.301 (vi) 8.699 4 7 . Ka = 1.73 × 10–5, pH = 8.73 4 8 . (i) 2.85, (ii) 4.0969, (iii) 4.5229,(iv) 4.699 (v) 4 9 . OX is more soluble 5 0 . 1.6 × 10–8 5 1 . 1.4 × 10–4 5 2 . [Cu+] = 5 × 10–11 M 2 55. 12 mg 5 3 . 10–18 M 5 4 . 1.0 × 10–5 mol/lit 5 6 . (a) no precipitation will occur, (b) a precipitate will form 5 7 . 1.6 × 10–3 5 8 . 4 × 10–7 mol/L AgBr, 9 × 10–7 mol/L AgSCN 5 9 . [F–] = 3 × 10–3 M 60 . 19.5 kg 6 1 . 2.8 × 10–3 M 6 2 . (a) 8.5 × 10–16, 5 × 10–12, 1.7 × 10–9 (b) I – (c) 1.7 × 10–5 (d) Br– = 2.9 × 10–4, I– = 5 × 10–8 6 3 . 4.9 × 10–10 6 4 . 5.5 × 10–3 [H+] < 0.96, 3.24 × 10–6 6 5 . (a) yes (b) 0.036 M 6 6 . s = 2.236 × 10–5 M 6 7 . 3.236 × 10–3 mol 6 8 . 1.09 mol
EXERCISE–04 [B] BRAIN STORMING SUBJECTIVE EXERCISE 1 . A solution of volume V contains n1 moles of QCl and n2 moles of RCl where QOH and ROH are two weak bases of dissociation constants k1 and k2 respectively. Show that the pH of the solution is given by pH 1 lo g k1 k2 V = k W (n1k2 k1n2 ) 2 State assumptions, if any. 2 . EDTA, often abbreviated as H4Y, forms ver y stable complexes with almost all metal ions. Calculate the fraction of EDTA in the fully protonated form, H4Y in a solution obtained by dissolving 0.1 mol Na4Y in 1 lit. The acid dissociation constants of H4Y : k1 = 1.02 × 10–2, k2 = 2.13 × 10–3, k3 = 6.92 × 10–7, k4 = 5.50 × 10–11 : 3 . Calculate the solubility of solid zinc hydroxide at a pH of 5,9 and 13. Given : Zn(OH)2(s) Zn(OH)2(aq) k1 = 10–6 M (1) Zn(OH) (aq) Zn(OH)+ + OH– k = 10–7 M (2) 2 2 Zn(OH)+ Zn2+ + OH– k3 = 10–4 M (3) Zn(OH)2(aq) + OH– Zn(OH)3– k4 = 103 M–1 (4) Zn(OH) – + OH– Zn(OH) 2– k = 10 M–1 (5) 3 4 5 4 . The standard free energy of formation for AgCl at 298 K is –109.7 kJ mole–1 . G° (Ag+) = 77.2 kJ/mole, G° (Cl–) = – 131.2 kJ/mole. Find the solubility of AgCl in 0.05 M KCl. Neglect any complication due to complexation :- 5 . Salt mixture containing Cu3(AsO4)2 (Ksp = 8 × 10–36) and Pb3(AsO4)2 (Ksp = 4.096 × 10–36) is shaken with water. Find the concentration of metal cations in the solution at equilibrium. Neglect any hydrolysis of the dissolved ions. 6 . (a) At what minimum pH will 1.0 × 10–3 mol of Al(OH)3 go into 1 L solution as [Al(OH)4–]. (b) At what minimum pH will 1.0 × 10–3 mol of Al(OH) go into 1 L solution as Al3+ ? 3 Given : Ksp [Al(OH)3] = 5.0 × 10–33 and for [Al(OH)4–] Al3+ + 4OH– . K = 1.3 × 10–34. 7 . A solution contains HCl, Cl2HCCOOH & CH3COOH at concentrations 0.09 M in HCl, 0.09 M in Cl2HCCOOH & 0.1 M in CH3COOH, pH for the solution is 1. Ionization constant of CH3COOH = 10–5. What is the magnitude of K for dichloroacetic acid ? 8 . A solution of ammonia bought for cleaning the windows was found to be 10% ammonia by mass, having a density of 0.935 g.mL–1. What is the pH of the solution. Take K for protonation of ammonia = 5.5 × 10–6. b 9 . The kw of water at two different temperature is :- T 25°C 50°C kw 1.08 × 10–14 5.474 × 10–14 Assuming that H of any reaction is independent of temperature, calculate the enthalpy of neutralization of a strong acid and strong base. 1 0 . What is the pH of a 1.0 M solution of acetic acid ? To what volume must 1 litre of the solution be diluted so that the pH of the resulting solution will be twice the original value. Given K = 1.8 × 10–5 :- a 1 1 . A handbook states that the solubility of methylamine CH NH (g) in water at 1 atm pressure at 25°C is 959 32 volumes of CH3NH2 (g) per volume of water (pkb = 3.39) :- (a) Estimate the max. pH that can be attained by dissolving methylamine in water. (b) What molarity NaOH (aq.) would be required to yield the same pH?
1 2 . Mixture of solutions. Calculate the pH of the following solutions. For H3PO4 ; K a1 7.5 103 , K a2 6.2 108 , K a3 1012 (a) 50 mL of 0.12 M H3PO4 + 20 mL of 0.15 M NaOH ; (b) 50 mL of 0.12 M H3PO4 + 40 mL of 0.15 M NaOH ; (c) 40 mL of 0.12 M H3PO4 + 40 mL of 0.18 M NaOH ; (d) 40 mL of 0.10 M H PO + 40 mL of 0.25 M NaOH. 34 1 3 . Mixtured of solutions. Calculate the pH of the following solution. Use data of above question & For H2CO3 ; K1 4.2 107 , K 2 4.8 1011 (a) 40 mL of 0.050 M Na2CO3 + 50 mL of 0.040 M HCl ; (b) 40 mL of 0.020 M Na3PO4 + 40 mL of 0.040 M HCl ; (c) 50 mL of 0.10 M Na3PO4 + 50 mL of 0.10 M NaH2PO4 ; (d) 40 mL of 0.10 M H PO + 40 mL of 0.10 M Na PO . 34 34 1 4 . When a 40 mL of a 0.1 M weak base is titrated with 0.16 M HCl, the pH of the solution at the end point is 5.23. What will be the pH if 15 mL of 0.12 M NaOH is added to the resulting solution :- 1 5 . A buffer solution was prepared by dissolving 0.05 mol formic acid & 0.06 mol sodium formate in enough water to make 1.0 L of solution. Ka for formic acid is 1.80 × 10–4. (a) Calculate the pH of the solution. (b) If this solution were diluted to 10 times its volume, what would be the pH ? (c) If the solution in (b) were diluted to 10 times its volume, what would be the pH? 1 6 . How many moles of sodium hydroxide can be added to 1.00 L of a solution 0.1 M in NH3 & 0.1 M in NH4Cl without changing the pOH by more than 1.00 unit ? Assume no change in volume. K (NH ) = 1.8 × 10–5. b3 1 7 . Calculate the OH– concentration and the H3PO4 concentration of a solution prepared by dissolving 0.1 mol of Na3PO4 in sufficient water to make 1 L of solution K1 = 7.1 × 10–3, K2 = 6.3 × 10–8, K3 = 4.5 × 10–13. 1 8 . If 0.00050 mol NaHCO is added to 1 litre of a buffered solution at pH 8.00, how much material will exist 3 in each of the three forms H2CO3, HCO3– and CO32– ? For H2CO3, K1 = 5 × 10–7, K2 = 5 × 10–13. 1 9 . Equilibrium constant for the acid ionization of Fe3+ to Fe(OH)+2 and H+ is 6.5 × 10–3. What is the max. pH, which could be used so that at least 95% of the total Fe3+ in a dilute solution. exists as Fe3+. 2 0 . How much Na2HPO4 must be added to one litre of 0.005 M solution of NaH2PO4 in order to make a 1 L of the solution of pH = 6.7 ? K = 7.1 × 10–3, K = 6.3 × 10–8 , K = 4.5 × 10–13 for H PO . 12 3 34 2 1 . The indicator phenol red is half in the ionic form when pH is 7.2. If the ratio of the undissociated form to the ionic form is 1 : 5, find the pH of the solution. With the same pH for solution, if indicator is altered such that the ratio of undissociated form to dissociated form becomes 1 : 4, find the pH when 50% of the new indicator is in ionic form :- 2 2 . A buffer solution, 0.080 M in Na PO and 0.020 M in Na PO , is prepared. The electrolytic oxidation of 24 34 1.0 m mol of the organic compound RNHOH is carried out in 100 mL of the buffer. The reaction is RNHOH + H2O RNO2 + 4H+ + 4e Calculate the approximate pH of the solution after the oxidation is complete ? 2 3 . A solution of weak acid HA was titrated with base NaOH. The equivalence point was reached when 36.12 mL of 0.1 M NaOH has been added. Now 18.06 mL of 0.1 M HCl were added to titrated solution, the pH was found to be 4.92. What will be the pH of the solution obtained by mixing 10 mL of 0.2 M NaOH and 10 mL of 0.2 M HA :- 2 4 . A weak base BOH was titrated against a strong acid. The pH at 1/4th equivalence point was 9.24. Enough strong base was now added (6m. eq.) to completely convert the salt. The total volume was 50 mL. Find the pH at this point :- 2 5 . An organic monoprotic acid [0.1 M] is titrated against 0.1 M NaOH. By how much does the pH change between one fourth and three fourth stages of neutralization ? If at one third stage of neutralization, the pH is 4.45 what is the dissociation constant of the acid ? Between what stages of neutralization may the pH change by 2 units ?
2 6 . The salt Zn(OH)2 is involved in the following two equilibria, Zn(OH) (s) Zn2+ (aq) + 2OH– (aq) ; K = 1.2 × 10–17 2 sp Zn(OH)2 (s) + 2OH– (aq) [Zn(OH)4]2– (aq) ; Kc = 0.13 Calculate the pH of solution at which solubility is minimum. 2 7 . What is the solubility of AgCl in 0.20 M NH ? 3 Given : Ksp(AgCl) = 1.7 × 10–10 M2, K1 = [Ag(NH3)+] / [Ag+][NH3] = 2.33 × 103 M–1 and K = [Ag(NH ) +] / [Ag(NH )+] [NH ] = 7.14 × 103 M–1 . 2 32 33 2 8 . Predict whether or not AgCl will be precipitated from a solution which is 0.02 M in NaCl and 0.05 M in KAg(CN) . Given K (Ag(CN) –) = 4.0 × 10–19 M2 and K (AgCl) = 2.8 × 10–10 M2. 2 inst 2 sp 2 9 . Equal volumes of 0.02 M AgNO3 and 0.02 M HCN were mixed. Calculate [Ag+] at equilibrium. Take K (HCN) = 9 × 10–10, K (AgCN) = 4 × 10–16 :- a sp 3 0 . Show that solubility of a sparingly soluble salt M2+A2– in which A2– ions undergoes hydrolysis is given by : S K sp [H ] [H ]2 1 K2 K1K 2 where K1 and K2 are the dissociation constant of acid H2A.Ksp is solubility product of MA. BRAIN STORMING SUBJECTIVE EXERCISE ANSWER KEY EXERCISE-4(B) 2 . 3.82 × 10–26 3 . 10 M, 1.12 × 10–6 M, 2 × 10–4 M 4 . K = 1.723 × 10–10 , s = 3.446 × 10–9 M 7 . ka2 = 1.25 × 10–2 sp 1 0 . V = 2.77 × 104 L 5 . [Cu+2] = 8.825 × 10–8 , [Pb+2] = 7.119 × 10–8 6 . (a) pH = 9.415 (b) pH = 4.23 8 . pH = 11.74 9 . Hneut = –51952.6 J = –51.95 kJ/mole 1 1 . (a) 13.097 (b) 0.1252 1 2 . (a) 2.12 (b) 4.66 (c) 7.2 (d) 12 1 3 . (a) 8.347 (b) 4.66 (c) 9.6 (d) 7.2 14. 9.1628 (b) pH = 3.846 (c) pH = 3.9899 1 5 . (a) pH = 3.823 1 6 . 0.0818 moles 1 7 . [OH–] = 3.73 × 10–2 M, [H3PO4] = 5.93 × 10–18 M 1 8 . [H2CO3] = 9.85 × 10–6 M, [HCO3–] = 4.9 × 10–4 M, [CO3–2] = 2.45 × 10–8 M 1 9 . pH = 0.908 2 0 . 1.6 m mole 2 1 . pH = 7.9, 7.3 22 . 7.81 2 3 . pH = 9 2 4 . pH = 11.22 1 10 2 6 . pH = 9.99, s = 10–9 M 2 5 . 0.9542, pk = 4.751, th & th stages of neutralization 2 9 . [Ag+] = 6.66 × 10–5 M a 11 11 2 7 . 9.6 × 10–3 M 2 8 . precipitate will occur
EXERCISE - 05 [A] JEE-[MAIN] : PREVIOUS YEAR QUESTIONS 1. How many litres of water must be added to 1 litre of an aqueous solution of HCl with a pH of 1 to create an aqueous solution with pH of 2 ? [AIEEE–2013] (A) 0.1 L (B) 0.9 L (C) 2.0 L (D) 9.0 L 2 . The pH of a 0.1 molar solution of the acid HQ is 3. The value of the ionization constant, Ka of this acid is :- [AIEEE–2012] (A) 1 × 10–7 (B) 3 × 10–7 (C) 1 × 10–3 (D) 1 × 10–5 3 . The Ksp for Cr(OH)3 is 1.6 × 10–30. The molar solubility of this compound in water is :- [AIEEE–2011] (A) 2 1.6 1030 (B) 4 1.6 1030 (C) 4 1.6 1030 / 27 (D) 1.6 × 10–30/27 4 . An acid HA ionises as HA H+ + A– The pH of 1.0 M solution is 5. Its dissociation constant would be :- [AIEEE–2011] (A) 1 × 10–10 (B) 5 (C) 5 × 10–8 (D) 1 × 10–5 5 . Solubility product of silver bromide is 5.0 × 10–13. The quantity of potassium bromide (molar mass taken as 120 g mol–1) to be added to 1 litre of 0.05 M solution of silver nitrate to start the precipitation of AgBr is :- [AIEEE–2010] (A) 5.0 × 10–8 g (B) 1.2 × 10–10 g (C) 1.2 × 10–9 g (D) 6.2 × 10–5 g 6 . In aqueous solution the ionization constants for carbonic acid are K1 = 4.2 × 10–7 and K2 = 4.8 × 10–11 Select the correct statement for a saturated 0.034 M solution of the carbonic acid :- [AIEEE–2010] (A) The concentration of H+ is double that of CO32– (B) The concentration of CO32– is 0.034 M (C) The concentration of CO32– is greater than that of HCO3– (D) The concentrations of H+ and HCO3– are approximately equal 7 . At 25° C, the solubility producct of Mg(OH)2 is 1.0 × 10–11. At which pH, will Mg2+ ions start precipitating in the form of Mg(OH)2 from a solution of 0.001 M Mg2+ ions ? [AIEEE–2010] (A) 8 (B) 9 (C) 10 (D) 11 8 . Solid Ba(NO3)2 is gradully dissolved in a 1.0 × 10–4 M Na2CO3 solution.At what concentration of Ba2+ will a precipitate begin to form? (KSP for Ba CO3 = 5.1 × 10–9) [AIEEE-2009] (D) 5.1 × 10–5 M (A) 8.1 × 10–8 M (B) 8.1 × 10–7 M (C) 4.1 × 10–5 M 9 . The pKa of a weak acid, HA, is 4.80. The pKb of a weak base, BOH, is 4.78. The pH of an aqueous solution of the corresponding salt. BA, will be - [AIEEE-2008] (A) 9.58 (B) 4.79 (C) 7.01 (D) 9.22 1 0 . In a saturated solution of the sparingly soluble strong electrolyte AglO3 (molecular mass = 283) the equilibrium which sets in is - [AIEEE-2007] AglO3 Ag ) + IO ( a q ) ( aq 3 If the solubility product constant Ksp of AgIO3 at a given temperature is 1.0 × 10– 8, what is the mass of AgIO3 contained in 100 ml of its saturated solution ? (A) 28.3 × 10– 2 g (B) 2.83 × 10– 3 g (C) 1.0 × 10– 7 g (D) 1.0 × 10– 4 g
1 1 . The solubility product of a salt having general formula MX2, in water is : 4 × 10– 12. The concentration of M2+ ions in the aqueous solution of the salt is - [AIEEE-2005] (A) 1.0 × 10– 4 M (B) 2.0 × 10– 6 M (C) 4.0 × 10– 10 M (D) 1.6 × 10– 4 M 1 2 . Hydrogen ion concentration in mol/L in a solution of pH = 5.4 will be - [AIEEE-2005] (A) 3.88 × 106 (B) 3.98 × 108 (C) 3.98 × 10– 6 (D) 3.68 × 10– 6 1 3 . The molar solubility in mol L–1 of a sparingly soluble salt MX4 is 's'. The corresponding solubility product is KSP. 's' is given in terms of KSP by relation : [AIEEE-2004] (A) s = (KSP / 128)1/4 (B) s = (128KSP)1/4 (C) s = (256KSP)1/5 (D) s = (KSP/256)1/5 1 4 . The solubility of Mg(OH)2 is x mole/lit. then its solubility product is- [AIEEE-2002] (A) x3 (B) 5x3 (C) 4x3 (D) 2x2 1 5 . The solubility in water of a sparingly soluble salt AB2 is 1.0 × 10– 5 mol L– 1. Its solubility product will be [AIEEE-2003] (A) 1 × 10– 15 (B) 1 × 10– 10 (C) 4 × 10– 15 (D) 4 × 10– 10 JEE-[MAIN] : PREVIOUS YEAR QUESTIONS ANSWER KEY EXERCISE -5[A] 1 . (D) 2 . (D) 3. (C) 4 . (A) (C) 8 . (D) 5 . (C) 6 . (D) 7. (A) 1 2 . (C) (C) 9 . (C) 1 0 . (B) 11. 1 3 . (D) 1 4 . (C) 15.
EXERCISE - 05 [B] JEE-[ADVANCED] : PREVIOUS YEAR QUESTIONS 1 . Which of the following statement(s) is/are correct ? [JEE 1998] (A) the pH of 1.0 × 10–8 M solution of HCl is 8 (B) the conjugate base of H PO – is HPO 2– 24 4 (C) autoprotolysis constant of water increases with temperature (D) when a solution of a weak monoprotic acid is titrated against a strong base, at half - neutralization point pH = (1/2) pK . a 2 . A buffer solution can be prepared from a mixture of- [JEE 1999] (A) sodium acetate and acetic acid in water (B) sodium acetate and hydrochloric acid in water (C) ammonia and ammonium chloride in water (D) ammonia and sodium hydroxide in water. 3 . The pH of 0.1 M solution of the following salts increases in the order- [JEE 1999] (A) NaCl < NH4Cl < NaCN < HCl (B) HCl < NH Cl < NaCl < NaCN 4 (C) NaCN < NH4Cl < NaCl < HCl (D) HCl < NaCl < NaCN < NH Cl 4 4 . An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250 mL. The volume of 0.1 N NaOH required to completely neutralise 10 mL of this solution is- [JEE 2001] (A) 40 mL (B) 20 mL (C) 10 mL (D) 4 mL 5 . For sparingly soluble salt ApBq, the relationship of its solubility product (Ls) with its solubility (S) is- [JEE 2001] (A) Ls = Sp+q, pp.qq (B) Ls = Sp+q, pp.qp (C) Ls = Spq pp.qq (D) Ls = Spq, (p.q)p+q 6 . A solution which is 10–3 M each in Mn2+, Fe2+, Zn2+ and Hg2+ is treated with 10–16 M sulphide ion. If K , sp MnS, FeS, ZnS and HgS are 10–15, 10–23, 10–20 and 10–54 respectively, which one will precipitate first ? [JEE 2003] (A) FeS (B) MnS (C) HgS (D) ZnS 7 . HX is a weak acid (K = 10–5). It forms a salt NaX (0.1 M) on reacting with caustic soda. The degree a of hydrolysis of NaX is- [JEE 2004] (A) 0.01 % (B) 0.0001 % (C) 0.1 % (D) 0.5 % 8 . CH NH (0.1 mole, K = 5 × 10–4) is added to 0.08 moles of HCl and the solution is diluted to one litre, 32 b resulting hydrogen ion concentration is- [JEE 2005] (A) 1.6 × 10–11 (B) 8 × 10–11 (C) 5 × 10–5 (D) 2 × 10–2
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