EXERCISE–02 BRAIN TEASERS SELECT THE CORRECT ALTERNATIVES (ONE OR MORE THEN ONE CORRECT ANSWERS) 1 . A mixutre of boric acid with ehtyl alcohol burns with green edged flame due to the formation of – (A) Ethyl borax (B) Ethyl borate (C) Methyl borax (D) Methyl borate 2 . AlCl3 on hydrolysis gives – (A) Al2O3.H2O (B) Al(OH)3 (C) Al2O3 (D) AlCl3.6H2O 3 . When a solution of sodium hydroxides is added in excess to the solution of potash alum, we obtain – (A) A white precipitate (B) Bluish white precipitate (C) A clear solution (D) A crystalline mass 4 . BCl3 does not exist as dimer but BH3 exist as dimer (B2H6) because – (A) Chlorine is more electronegative than hydrogen (B) There is p – p back bonding in BCl3 but BH3 does not contain such multiple bonding (C) Large sized chlorine atoms do not fit in between the small boron atoms whereas small sized hydrogen atoms get fitted in between boron atoms (D) None of the above 5 . Amorphous boron on burning in air forms – (A) B(OH)3 (B) Mixutre of B2O3 and BN (C) Only B2O3 (D) Only BN 6 . Which of the following statements is correct ? (A) BCl3 and AlCl3 are both Lewis acids and BCl3 is stronger than AlCl3 (B) BCl3 and AlCl3 both Lewis acids and AlCl3 is stronger that BCl3 (C) BCl3 and AlCl3 are both equally strong Lewis acids (D) Both BCl3 and AlCl3 are not Lewis acids. 7 . Which one of the following does not exist in the free form ? (A) BF3 (B) BCl3 (C) BBr3 (D) BH3 8 . Thermite is a mixture of – (A) 3 Parts of powdered Al and 1 part of Fe2O3 (B) 1 part of powdered Al and 3 parts of Fe2O3 (C) 1 part of powdered Al and 1 part of Fe2O3 (D) 2 Parts of powdered Al and 1 part of Fe2O3 9 . Borax is used as cleansing agent because on dissolving in water it gives – (A) Alkaline solution (B) Acidic solution (C) Bleching solution (D) Colloidal solution 1 0 . Trisilylamine [ N(SiH3)3] has a – (B) Tetrahedral geometry (A) Planar geometry (D) None of these (C) Pyramidal geometry
1 1 . The halide that is not hydrolysed is – (A) SiCl4 (B) SiF4 (C) CCl4 (D) PbCl4 1 2 . What is false about N2O5 ? (A) It is anhydride of HNO3 (B) It is a powerful oxidizing agent (C) Solid N2O5 is called nitronium nitrate (D) Structure of N2O5 contains no [NO] bond 1 3 . SbCl3 and BiCl3 on hydrolysis gives – (A) Sb+3 and Bi+3 (B) Sb(OH)3 and Bi(OH)3 (D) None (C) SbOCl and BiOCl 1 4 . The percentage of nitrogen in urea is about – (A) 70 (B) 63 (C) 47 (D) 28 1 5 . Sequence of acidic character is – (A) SO2 > CO2 > CO > N2O5 (B) SO2 > N2O5 > CO > CO2 (C) N2O5 > SO2 > CO > CO2 (D) N2O5 > SO2 > CO2 > CO 1 6 . Tip of saftymatch stick are made up of – (A) Sulphur and potassium (B) Sulphur (C) Sulphur, dichromate and phosphorus (D) Sulphur, dichromate and potassium 1 7 . Of the following, which has three electron bond in its structure ? (A) Nitrous oxide (B) Nitric oxide (C) Dinitrogen trioxide (D) Nitrogen pentoxide 1 8 . Which of the following leaves no residue on heating ? (A) Pb(NO3)2 (B) NH4NO3 (C) Cu(NO3)2 (D) NaNO3 1 9 . H2SO4 has very high corrosive action on skin because – (A) it reacts with proteins (B) it acts as an oxidising agent (C) it acts as a dehydrating agent (D) it acts as dehydrating agent and absorption of water is highly exothermic 2 0 . A black sulphide when treated with ozone becomes white. The white compound is – (A) ZnSO4 (B) CaSO4 (C) BaSO4 (D) PbSO4 2 1 . Which of the following does not react with AgCl – (A) Na2S2O3 (B) NH4OH (C) NaNO3 (D) NH3
2 2 . By passing H2S gas in acidified KMnO4 solution, we get – (A) K2S (B) S (C) K2SO3 (D) MnO2 2 3 . Chloride of lime is – (A) CaOCl2 (B) Ca(OCl)2 (C) CaCl2 (D) (CaO)2 Cl 2 4 . Which one of the following oxy acid of fluorine exists ? (A) HOF (B) HFO3 (C) HFO4 (D) HFO2 2 5 . Chromyl chloride test is performed for the confirmation of the presence of the following in mixture – (A) SO42– (B) Cr+++ (C) Cl– (D) Cr+++ and Cl– 2 6 . Iodine gas turns strach iodide paper – (A) Blue (B) Red (C) Colourless (D) Yellow 2 7 . Essential trace element involved in physiology of thyroid glands – (A) K (B) Mg (C) Ni (D) I2 2 8 . When chlorine is passed over dry slaked lime at room temperature, the main reaction product is – (A) Ca(ClO2)2 (B) CaCl2 (C) CaOCl2 (D) Ca(OCl2)2 2 9 . Iodine is formed when KI reacts with a solution of – (A) ZnSO4 (B) CuSO4 (C) FeSO4 (D) (NH4)2SO4 3 0 . Which amongst the following reactions cannot be used for the preparation of the halogen acid ? (A) 2KBr + H2SO4(Conc.) K2SO4 + 2HBr (B) 2NaCl + H2SO4(Conc.) NaHSO4 + HCl (C) NaHSO4 + NaCl Na2SO4 + HCl (D) CaF2 + H2SO4(conc.) CaSO4 + 2HF 3 1 . HI can be prepared by all the following methods except – (A) Pl3 + H2O (B) KI + H2SO4 (C) H2 + I2 (D) I2 + H2S 3 2 . When I2 is passed through KCl, KF, KBr solution – (A) Cl2 and Br2 are evolved (B) Cl2 is evolved (C) Cl2, Br2, F2 are evolved (D) None of these 3 3 . Which two of the following salts are used for preparing iodized salt– (i) KIO3 (ii) KI (iii) I2 (iv) HI (A) (i) and (ii) (B) (i) and (iii) (C) (ii) and (iv) (D) (iii) and (iv) 3 4 . Helium is obtained from which of the following.? (A) Natural gases trapped under rock formations. (B) Liquid air (C) Radioactive decay (D) Gasoline 3 5 . The statement, which prompted Neil Bartlett to prepare the first noble gas compound was – (A) Xe-F bond has high bond energy (B) F2 has exceptionally low bond energy (C) PtF6 is a strong oxidant (D) O2 molecule and Xe atom have very similar ionization energies.
3 6 . Pick out the correct statement for XeF6 (A) XeF6 is hydrolysed partially to form XeOF4 (B) It react with SiO2 to form XeOF4 (C) On complete hydrolysis, it forms XeO3 (D) All 3 7 . The molecular shapes of diborane is shown: H H 1.33Å 1.19Å H Consider the following statements for diborane B B 1. Boron is approximately sp3 hybridised H HH 2 . B-H-B angle is 180º 3 . There are two terminal B-H bonds for each boron atom 4. There are only 12 bonding electrons available Of these statements – (A) 1, 3 and 4 are correct (B) 1, 2 and 3 are correct (C) 2, 3 and 4 are correct (D) 1, 2 and 4 are correct 3 8 . Borax is actually made of two tetrahedral and two triangular units joined together and should be written as : Na2 [B4O5(OH)4] · 8H2O. Consider the following statements about borax: 1 . Each boron atom has four B-O bonds 2 . Each boron atom has three B-O bonds 3 . Two boron atoms have four B-O bonds while other two have three B-O bonds 4 . Each boron atom has one-OH groups Select correct statement(s) – (A) 1, 2 (B) 2, 3 (C) 3, 4 (D) 1, 3 3 9 . Three allotropes (A), (B) and (C) of phosphorous in the following change are respectively – 470 K B A 1200 atm 570 K C CO2– atm (A) White, black, red (B) Black, white, red (C) Red, black, white (D) Red, violet, black 4 0 . One mole of calcium phosphide on reaction with excess of water gives – (A) One mole of phosphine (B) Two moles of phosphoric acid (C) Two moles of phosphine (D) One mole of phosphorus penta-oxide 4 1 . Ca + C2 CaC2 N2 A Compound (A) is used as a/an – (A) Fertilizer (B) Dehydrating agent (C) Oxidising agent (D) Reducing agent 4 2 . Which one of the following statements is not true regarding diborane? (A) It has two bridging hydrogens and four perpendicular to the rest. (B) When methylated, the product is Me4B2H2 (C) The bridging hydrogens are in a plane perpendicular to the rest. (D) All the B–H bond distances are equal.
4 3 . A red coloured mixed oxide (X) on treatment with concentrate HNO3 gives a compound (Y). (Y) with HCl, produces a chloride compound (Z) which can also be produced by treating (X) with concentrate HCl. Compounds (X), (Y) and (Z) will be – (A) Mn3O4, MnO2, MnCl2 (B) Pb3O4, PbO2, PbCl2 (C) Fe3O4, Fe2O3, FeCl2 (D) Fe3O4, Fe2O3, FeCl3 4 4 . Match List-I with List-II List-I Chemical reaction List-II Name of process (a) Contact process (1) 4NH + 5O 800ºC/Pt 4NO + 6H O 32 2 (2) 4HCl + O 3230ºC/CuCl2 2Cl + 2H O (b) Ostwald's process (c) Deacon's process 2 450-500º/V2O5 2 2 (d) Haber's process (C) 1-a, 2-d, 3-c, 4-b (3) 2SO + O 2SO 2 2 3 (4) 2N + 3H Fe+Mo 2NH 22 3 (A) 1-a, 2-b, 3-d, 4-c (B) 1-b, 2-c, 3-a, 4-d (D) 1-a, 2-c, 3-b, 4-d 4 5 . A gas which exists in three allotropic forms and is – (A) SO2 (B) SO3 (C) CO2 (D) NH3 (D) N2O5 4 6 . HNO3 + P4O10 HPO3 + A ; The product A is – (A) N2O (B) N2O3 (C) NO2 4 7 . Which of the following statements is/are correct regarding B H ?– 26 (A) Banana bonds are longer but stronger than normal B–H bonds (B) B2H6 is also known as 3c-2e compound (C) The hybrid state of B in B2H6 is sp3 while that of sp2 in BH3 (D) It cannot be prepared by reacting BF3 with LiBH3 in the presence of dry ether 4 8 . Which of the following pairs of nitrates gives the same gaseous products on thermal decomposition? (A) KNO3 and Pb(NO3)2 (B) KNO3 and NaNO3 (C) Pb(NO3)2 and Cu(NO3)2 D) NaNO3 and Ca(NO3)2 4 9 . When an inorganic compound (X) having 3c - 2e as well as 2c -2e bonds reacts with ammonia gas at a certain temperature, gives a compound (Y) iso-structural with benzene. Compound (X) with ammonia at a high temperature, produces a hard substance (Z). Then – (A) (X) is B2H6 (B) (Z) is known as inorganic graphite (C) (Z) having structure similar to graphite (D) (Z) having structure similar to (X) 5 0 . Boric acid – (A) Exists in polymeric form due to inter-molecular hydrogen bonding (B) Is used in manufacturing of optical glasses (C) Is a tri-basic acid (D) With borax, it is used in the preparation of a buffer solution. 5 1 . Select correct statement(s) – (A) Borax is used as a buffer (B) 1 M borax solution reacts with equal volumes of 2 M HCl solution (C) Titration of borax can be made using methyl orange as the indicator (D) Coloured bead obtained in borax-bead test contains metaborate.
5 2 . Select corect statement about B2H6 – (A) Bridging groups are electron-deficient with 12 valence electrons (B) It has 2c-2e B–H bonds (C) It has 3c-2e B-H-B bonds (D) All of above are correct statements 5 3 . Which of the following is/are correct for group 14 elements – (A) The stability of dihalides are in the order CX2 < SiX2 < GeX2 < SnX2 < PbX2 (B) The ability to form p-p multiple bonds among themselves increases down the group (C) The tendency for catenation decreases down the group (D) They all form oxides with the formula MO2 54. The solubility of anhydrous AlCl3 and hydrous AlCl in diethyl ether are S and S respectively. Then – 3 1 2 (A) S1 = S2 (B) S1 > S2 (C) S1 < S2 (D) S1 < S1 but not S1=S2 5 5 . Concentrated HNO3 reacts with iodine to give – (A) HI (B) HOI (C) HOIO2 (D) HOIO3 5 6 . Conc. H2SO4 cannot be used to prepare HBr from NaBr because it – (A) Reacts slowly with NaBr (B) Oxidises HBr (C) Reduces HBr (D) Disproportionates HBr 5 7 . CH2 COOH P4O10,150ºC X. Compound (X) is – COOH (A) Malonic acid (B) Carbon suboxide (C) Tartaric acid (D) Acetic acid 58. H3BO3 T1 X T2 Y red hot BO if T < T then X and Y respectively are – 22 1 2 (A) X = Metaboric acid and Y = Tetraboric acid (B) X = Tetraboric acid and Y = Metaboric acid (C) X = Borax and Y = Metaboric acid (D) X = Tetraboric acid and Y = Borax 5 9 . In a molecule of phosphorus (V) oxide, there are – (A) 4P – P, 10P – O and 4P = O bonds (B) 12P – O and 4P = O bonds (C) 2P – O and 4P = P bonds (D) 6P – P, 12P – O and 4P = P bonds 6 0 . Conc. HNO3 is yellow coloured liquid due to – (A) Dissolution of NO in conc. HNO3 (B) Dissolution of NO2 in conc. HNO3 (C) Dissolution of N2O in conc. HNO3 (D) Dissolution of N2O3 in conc. HNO3 6 1 . When chlorine gas is passed through an aqueous solution of a potassium halide in the presence of chloroform, a voilet colouration is obtained. On passing more of chlorine water, the voilet colour is disappeared and solution becomes colourless. This test confirms the presence of ............. in aqueous solution. – (A) Chlorine (B) Fluorine (C) Bromine (D) Iodine
6 2 . An inorganic salt (A) is decomposed at about 523 K to give products (B) and (C). compound (C) is a liquid at room temperature and is neutral to litmus paper while oxide (B) on burning with white phosphorous, given a dehydrating agent (D). compounds (A), (B), (C) and (D) will be identified as – (A) NH4NO3, N2O, H2O, P2O5 (B) NH4NO2, N2O, H2O, P2O5 (C) CaCO3, CaO, H2O, CaCl2 (D) CaCO3, CaO, H2O, Ca(OH)2 6 3 . Aqueous solution of borax reacts with 2 mol of acids. This is because of – (A) Formation of 2 mol of B(OH)3 only. (B) Formation of 2 mol of [B(OH)4]– only. (C) Formation of 1 mol each of B(OH)3 and [B(OH)4]– (D) Formation of 2 mol each of [B(OH)4]– and B(OH)3, of which only [B(OH)4]– reacts with acid 6 4 . Borax is used as a buffer since – (A) Its aqueous solution contains equal amount of weak acid and its salt (B) It is easily available (C) Its aqueous solution contains equal amount of strong acid and its salt (D) Statement that borax is a buffer, is wrong. 6 5 . When fluoride is heated with conc.H2SO4 and MnO2 the gas evolved is – (A) HF (B) F2 (C) SF4 (D) None BRAIN TEASERS ANSWER KEY EXER CISE -2 Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans. B B C C B A DBA A C DC C D Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans. C B B D D C B A A C A D C B A Que. 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 A n s . B D A A ,C D D A C A C A D B B B Que. 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A n s . D A ,B,C B,C A ,B,C A ,B,D A,B,C,D B,C A ,C,D B C B B A B B Que. 61 62 63 64 65 Ans. D A D A A
EXERCISE–03 MISCELLANEOUS TYPE QUESTIONS TRUE / FALSE 1 . Goldschmidt thermite process is used in the extraction of aluminium. 2 . Cryolite is added to alumina as to lower the fusion temperature and make the mass good conductor of electricity. 3 . Nitrous acid acts both as an oxidising and a reducing agent. 4 . NF3 is stable but NCl3 and NI3 are explosive in nature. 5 . Bleaching action of SO2 is due to reduction and temporary. 6 . Mercury in presence of ozone is oxidised to mercuric oxide. 7 . Hydrofluoric acid cannot be kept in glass vessels. 8 . The amount of chlorine obtained from a sample of bleaching powder by treatment with excess of dilute acid or CO2 is called available chlorine. FILL IN THE BLANKS 1 . The increase in solubility of iodine in an aqueous solution of KI is due to the formation of ................. 2 . Silver fluoride is fairly.................in water. 3 . HI cannot be prepared by the action of conc. H2SO4 on KI because H2SO4 is an ...............agent. 4 . Antichlor is a compound which converts ................into ...................... 5 . Iodine reacts with hot NaOH solution giving the products as NaI and ........................... 6 . In the known interhalogen compounds, the maximum number of halogen atom is ....................... 7 . Conc. HNO3 reacts with iodine to give ................... 8 . The only halogen that is not found in nature is ...................... 9 . Tincture of iodine contains I2,..............and...................... 1 0 . Iodine deficiency in diet is known to cause........................ MATCH THE COLUMN Column-II 1. Column-I (p) All hydrogen are ionizable in water (q) Lewis acid (A) Hypo phosphoric acid (r) Monobasic in water (B) Pyro phosphoric acid (s) sp3 hybridized central atom (C) Boric acid (D) Hypo phosphorus acid
ASSERTION & REASON QUESTIONS 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 : Silicones are very inert polymers. Because Statement -II : Both Si—O and Si—C bond energies are very high. 2 . Statement -I : Chlorine gas disproportionates in hot & conc. NaOH solution Because Statement -II : NaCl and NaOCl are formed in the above reaction. 3 . Statement -I : Al(OH)3 is amphoteric in nature. Because Statement -II : It can not be used as an antacid. 4 . Statement -I : Oxygen is more electronegative than sulphur, yet H2S is acidic, while H2O is neutral. Because Statement -II : H–S bond is weaker than O–H bond. 5 . Statement -I : Conc. H2SO4 can not be used to prepare pure HBr from NaBr. Because Statement -II : It reacts slowly with NaBr. 6 . Statement -I : Aluminium and zinc metal evolve H2 gas from NaOH solution. Because Statement -II : Several non-metals such as P, S, Cl, etc. yield a hydride instead of H2 gas from NaOH 7 . Statement -I : Borax bead test is applicable only to coloured salt. Because Statement -II : In borax bead test, coloured salts are decomposed to give coloured metal metaborates. 8 . Statement -I : Cl2 gas bleaches the articles permanently. Because Statement -II : Cl2 is a strong reducing agent. 9 . Statement -I : HClO is stronger acid than HBrO Because Statement -II : Greater is the electronegativity of the halogen, greater will be attraction of electron pair towards it and hence more easily the H+ ion will be released.
COMPREHENSION BASED QUESTIONS Comprehension # 1 The name 'Silica' covers an entire group of minerals, which have the general formula SiO2, The most common of which is quartz. Quartz is a framework silicate with SiO4 tetrahedral arranged in spirals. the spirals can turn in a clockwise or anticlockwise direction – a feature that results in there being two mirror images, optically active, varieties of quartz. 1 . The following pictures represent various silicate anions. Their formulae are respectively – = Silicon = Oxygen (A) SiO 2 Si O 2 (B) SiO 4 Si O 8 3 7 4 10 3 3 (C) SiO 2 Si O 2 (D) SiO 4 Si O 8 4 9 3 7 3 3 2. Si O 6 (having three tetrahedral) is represented as – 9 3 (A) (B) (C) Both (D) None of these 3 . The silicate anion in the mineral kaolinite is a chain of three SiO4 tetrahedral that share corners with adjacent tetrahedral. The mineral also contains Ca2+ ions, Cu2+ ions, and water molecules in a 1:1:1 ratio. Mineral is represented as – (A) CaCuSi3O10 · H2O (B) CaCuSi3O10 · 2H2O (C) Ca2Cu2Si3O10 · 2H2O (D) None of these Comprehension # 2 Silicons are synthetic polymers containing repeating R2SiO units. Since, the empirical formula is that of a ketone (R2CO), the name silicone has been given to these materials. Silicones can be made into oils, rubbery elastomers and resins. they find a variety of applications because of their chemical inertness, water repelling nature, heat-resistance and good electrical insulating property. Commercial silicon polymers are usually methyl derivatives and to a lesser extent phenyl derivatives and are synthesised by the hydrolysis of R2SiCl2 [R = methyl (Me) or phenyl ()] Me Me Me Me2SiCl2 H2O ||| O—Si—O—Si—O—Si—O— ||| Me Me Me 1 . If we mix Me3SiCl with Me2SiCl2, we get silicones of the type – Me Me Me Me Me Me |||| || (A) Me—Si—O—Si—O—Si—O—Si—Me —O—Si—O—Si—O– |||| || Me Me Me Me (B) O O || (C) Both of the above —O—Si—O—Si—O– || Me Me (D) None of the above
2 . If we start with MeSiCl3 as the starting material, silicones formed is – Me Me Me Me |||| (A) Me—Si—O—Si—O—Si—O—Si—Me |||| Me Me Me Me Me Me || —O—Si—O—Si—O– || (B) O O || —O—Si—O—Si—O– || Me Me (C) Both of the above (D) None of the above MISCELLANEOUS TYPE QUESTION ANSWER KEY EXERCISE -3 True / False 1. F 2. T 3. T 4. T 5. T 6. F 7. T 8. T Fill in the Blanks 1.KI3 2.Soluble 3. Oxidising 4. Cl2, Hydrochloric acid 5. NaIO3 6.Eight 7.HIO3 8.At 9. KI, Reactified spirit 10. Goiter Match the Column 1. (A) p,s ; (B) s ; (C) q,r ; (D) r,s Assertion - Reason Questions 1.A 2.C 3.C 4.A 5.C 6.B 7. A 8.C 9.A Comprehension Based Questions Comprehension # 1 : 1. B 2. B 3.C Comprehension # 2 : 1.A 2.B
EXERCISE–04 [A] CONCEPTUAL SUBJECTIVE EXERCISE 1 Colourless salt (A) + NaOH (excess) gas (B) giving white fumes with HCl + alkaline solution (C) (C) + Zn gas (B) (A) gas (D) + liquid (E) D,E Both triatomic Identify (A,B,C,D) and (E) 2 Complete and balance the following reactions- (a) Cu + dil. HNO NO + ......+......... 3 (b) Pb (NO ) heat PbO +......+........ 32 (c) CuSO + NH OH(excess) ........... 4 4 (d) AgCl + NH OH .............. 4 3 Aqua-regia dissolves gold. Write reaction. 4 Precipitation of second group sulphides in qualitative analysis is carried out with H S in presence of HCl and 2 not nitric acid.Why? 5 KMnO should not be dissolved in conc. H SO . Why? 4 24 6 What happens when H2S gas is passed through nitric acid ? 7 What happens when – (1) Hydrogen sulphide is bubbled through an aqueous solution of sulphur dioxide. (2) Hydrogen sulphide is passed through acidified ferric chloride solution. (3) Sulphur is boiled with caustic soda solution. 8 Sodium salt (A) of a dibasic acid HCl gas (B) and clear solution gas (B) and clearsom turns K Cr O to 2 27 green and also lime water milky. identify (A) and (B). 9 A certain salt 'X' gives the following test. (i) Its aqueous solution is alkaline to litmus. (ii) On strongly heating it swells to give glassy bead. (iii) When concentrated H SO is added to solution of 'X', white crystals of a weak acid. seperate out. 24 Identify 'X' and write down all reaction. 1 0 SnCl gives white precipitate with HgCl which turns grey later on, but SnCl does not. Explain why ? 22 4 1 1 Identify A and B (Compound/reaction condition) PbS Heat A + PbS B Pb + SO in air 2 1 2 A bottle of liquor ammonia should be cooled before opening.Why ? 1 3 lodine is liberated in the reaction between Kl and Cu2+ but chlorine is not liberated when KCl is added to Cu2+. Why? 1 4 What happens when an aqueous solution of hydrazine reacts with: (i) An aqueous solution of I 2 (ii) An alkaline solution fo copper sulphate (iii) An aqueous alkaline solution of potassium ferricyanide (iv) an ammoniacal solution of silver nitrate.
1 5 An acid (A) is pale-blue. The potassium salt of this acid does not give any reaction with BaCl but gives white 2 crystalline precipitate (B) with Ag+ ions. The acid (A) reacts with urea to liberate two gases (C) and (D). Gas (D) is used in synthesis of Urea also. On adding thiourea in acid (A) followed by addition of FeCl /dilute HCl red 3 coloured substance (E) is obtained. Identify substances (A) to (E). CONCEPTUAL SUBJECTIVE EXERCISE ANSWER KEY EXERCISE -4(A) 1 . (A) NH4 NO3 (B) NH3 (C) (NaNO3 +NaOH) (D) N2O (E) H2O 2 . (a) 2HNO3 O + 2NO +3(O) 3Cu +3(O) +6HNO3 3Cu (NO3 )2 +3H2 O 3Cu + 8HNO3 3Cu (NO3 )2 +2NO + 4H2 O (b) 2Pb(NO3 )2 2PbO + 4NO2 +O2 (c) CuSO4 + 2NH4 OH Cu (OH2 ) +(NH4)2 SO4 Cu (OH2) + (NH4)2 SO4 + 2NH4 OH [Cu(NH3 )4] SO4 +4H2O (g) AgCl + NH4 OH AgOH + NH4 Cl AgOH + NH4 Cl +NH4 OH Ag (NH3 )2 Cl+2H2 O AgCl +2NH4OH Ag(NH3)2 Cl + 2H2 O 3 . Noble metals like gold, platinum, iridium, rhodium etc., do not react with nitric acid. However, these metals dissolve in aqua-regia (3 parts conc. HCl and one part conc. HNO3). Aqua-regia gives nacent chlorine which attacks these metals. Gold: [HNO3 + 3HCl NOCl + 2H2O + 2Cl] × 3 Nitrosyl chloride [Au + 3Cl AuCl3] × 2 [AuCl3 + HCl HAuCl4] × 2 2Au + 3HNO3 + 11 HCl 2HAuCl4 + 3NOCl + 6H2O Chloroauric acid 4 . HNO3, a strong oxidant, will oxidise H2 S to give colloidal sulphur. Thus precipitation of second group sulphide will not occur. H2 S [O] H2 O +S HNO3 5 . KMnO4 forms explosive covalent compound,Mn2 O7 with conc. H2 SO4 . 2KMnO4 + H2 SO4 conc. K2 SO4 + Mn2 O7 +H2 O However, it can be dissolved in dil. H2 SO4 to give nascent oxygen if it is to be used as oxidant. 6 . Yellow colloidal sulphur is formed. 7 . (1) 2HNO3 + H2 S 2NO2 + 2H2 O + S (2) (Moist) SO2 + 2H2 S 3S + 2H2 O (3) 2 FeCl3 + H2 S 2FeCl2 + 2HCl+S 4S + 6NaOH Na2 S2 O3 +2Na2S +3H2O excess sulphur Na2S5
9 . Na2 B4 O7. 10H2 O Na2 B4O7 +7 H2 O 2NaOH +4H3 BO3 Weak Due to presence of NaOH. the aqueous solution is alkaline to litmus. Na2 B4 O7. 10H2 O Na2 B4 O7 (2NaBO2 + B2O3) Glassy Bead Na2 B4 O7 + H2 SO4 + 5H2O Na2SO4 + 4H3 BO3 . 1 0 . SnCl2 is strong reducing agent and reduces HgCl2 to Hg2Cl2(white) which is further reduced to Hg (grey). SnCl2 + HgCl2 SnCl4 +Hg2 Cl2 SnCl2 + Hg2Cl2 SnCl4 + 2Hg 1 1 . A = PbO or PbSO4 B = high temperature 1 2 . It should be cooled to lower the pressure of NH3 inside the bottle, otherwise NH3 will bump out of the bottle. 1 3 . The I– ion acts as strong reducing agent where as Cl– acts as reductant only in presence of strong oxidant and therefore Kl reduces Cu2+ to Cu+ Cu2+ + 4Kl Cu2 I2 +I2 + 4K+ 1 4 . (i) N2H4 + 2I2 N2 + 4HI (ii) N2H4 + 2 CuSO4 + 4KOH N2 + 2Cu + 2K2SO4 + 4H2O (iii) 4K3 [Fe(CN)6] + 4KOH + N2H4 4K4[Fe(CN)6] + 4H2O + N2 (iv) N2H4 + 2NH4OH + 2AgNO3 N2 + 2Ag + 2NH4NO3 + 2H2O 1 5 . (A) = HNO2(Nitrous acid) ; (B) = AgNO2 (Silver nitrite) (C) = N2 ; (D) = CO2 ; (E) = Fe(SCN)3 (Ferric thiocyanate) (i) KNO2 + Ag+ AgNO2 + K+ (B) Silver nitrite (ii) 2HNO2 + NH2CONH2 2N2 + CO2 + 3H2O (A) (Urea) (C) (D) (iii) HNO2 + NH2CSNH2 N2 +H+ + SCN– + 2H2O (A) Thioureao FeCl3 + 3SCN– [Fe(SCN)3] + 3Cl– (E) Ferric thiocyanate
EXERCISE–04 [B] BRAIN STORMING SUBJECTIVE EXERCISE 1 . A white crystalline comp. 'A' Swell up on heating and gives violet coloured flame on bunsen flame Its, aq. solution gives the following reaction. (i) A white ppt. with BaCl2 in presence of HCl. (ii) When treated with excess of NH4 OH it gives white gelatinous ppt., which dissolve in NaOH. 2 . A binary salt (A) on reaction with H2 O gives (B) aq. and (C) hydrocarbon. (C) gas on passing into ammonical AgNO3 gives white ppt. (D). CO2 gas turns (B) aq. milky. Identify (A), (B), (C) and (D). 3 . FeCl3 solution gives blood red colour with NH4 SCN. If H2 S gas is passed and filtered then filtrate does not give red colour with NH4 SCN Explain. 4 . How will you obtain the following from sulphuric acid. (a) SO2 (b) SO3 (c) SO2 Cl2 5 . Complete the following reactions: CH2 (ii) H(i)2BO22H/O6H– A 6 . An inorganic compound (A) of S, Cl and oxygen has vapour density 67.5. It reacts with water to form two acids (B) and (C). (A) also reacts with KOH(aq) to forms two salts (D) and (E). (D) and (E) gives white precipitate with AgNO3 and BaCl2 solutions respectively. What are (A) to (E)? 7 . A certain compound (X) gives brick red flame on performing the flametest and shows the following reactions. (i) When KI is added to an aqueous suspension of (X) containing acetic acid, iodine is liberated. (ii) When CO2 is passed through an aqueous suspension of (X) the turbidity transforms to a ppt. (iii) When a paste of (X) in water is heated with ethyl alcohol, a product of anaesthetic use is obtained. Identify (X) and write down chemical equations for reactions at step (i), (ii) and (iii).
CONCEPTUAL SUBJECTIVE EXERCISE ANSWER KEY EXERCISE -4(B) 1 . A : K SO · Al (SO ) · 24 H O 24 2 43 2 Al (SO ) + 6NH OH 2Al(OH) + 3(NH ) SO 2 43 4 3 42 4 NaOH NaAlO + 2H O 22 2. (A) : CaC (Ca2+ , C 2 binary) 2 2 (B) : Ca(OH) 2 (C) : C H 22 (D) : C Ag 22 3 . FeCl on reacting with NH SCN gives complex ion [Fe(SCN)]2+ which is of red colour. 34 FeCl3 + NH4 SCN [Fe(SCN)]Cl2 + NH4 Cl blood red colour FeCl3 while reacting with H2 S, gives FeCl2 which is not reacting with NH4 SCN. So no colour is obtained. 4 . (a) SO is obtained by heating copper with conc. H SO 2 24 Cu + 2H SO CuSO + SO + 2H O 2 4 4 2 2 It can also be obtained by boiling sulphur with conc. H SO . 24 S + 2H SO 3SO + 2H O 24 2 2 (b) When treated with P O H SO loses water and forms SO 25 2 4 3 H SO + P O 2HPO + SO 24 25 3 3 (c) SO Cl is formed when conc. H SO is treated with excess of PCl . 22 24 5 H SO + 2PCl SO Cl + 2POCl + 2HCl 24 5 2 2 3 CH2 5 . (i) B2H6 (C6H12CH2)3B2 CH2OH (ii) H2O2/OH– 6 . Vapour density of S, Cl and oxygen compound = 67.5 Molecular weight of compound = 135 the molecular, weight suggest it may be SO Cl 22 The give reaction are (i) SO Cl + 2H O 2HCl + H SO 22 2 24 (A) (B) (C)
(ii) SO Cl + 4KOH K SO + 2KCl + 2H O 22 24 2 (D) (E) (iii) K SO + BaCl BaSO + 2KCl 24 2 4 (D) Insoluble KCl + AgNO AgCl + KNO 3 3 (E) Insoluble 7 . (X) gives brick red flame so, it contains Ca2+. Reactions (i), (ii) and (iii) suggest that the probable compound is bleaching powder (CaOCl ). 2 Rxn (i) CaOCl + HO Ca(OH) + Cl2 2 2 2 smell (ii) CaOCl2 + 2CH3COOH Ca(CH3COO)2 + Cl2 + H2O (X) 2KI + Cl 2KCl + I 2 2 (iii) CaOCl (aq.) + CO CaCO + Cl 2 2 3 2 Turbid white ppt (iv) CaOCl + HO Ca(OH) + Cl 2 2 2 2 (X) C H OH + Cl CH CHO + 2HCl 25 2 3 CH5CHO + 3Cl2 CCl3 · CHO + 3HCl Ca(OH) + 2CCl CHO 2CHCl + (HCOO) Ca 2 3 3 2 (Anaesthetic)
EXERCISE–05 [A] PREVIOUS YEARS QUESTIONS 1 . Aluminium is industrially prepared by: [AIEEE-2002] (1) Fused cryolite (2) Bauxite ore (3) Alunite (4) Borax 2 . In case of nitrogen NCl is possible but not NCl while in case of phosphorous, PCl as well as PCl are possible. 35 35 This is due to :- [AIEEE-2002] (1) Availability of vacant d-orbitals in P butnot in N (2) Lower electronegativity of P than N (3) Lower tendency of H-bond formation in P than N (4) Occurence of P in solid while N in gaseous state at room temperature 3 . Which products are expected from the disproportionation of hypochlorous acid : [AIEEE-2002] [AIEEE-2002] (1) HClO and Cl O (2) HClO and HClO 32 2 (3) HCl and Cl O (4) HCl and HClO 2 3 4 . Identify the incorrect statement among the following (1) Ozone reacts with SO to give SO 23 (2) Silicon reacts with NaOH(aq.) in the presence of air to give Na SiO and H O 23 2 (3) Cl reacts with excess of NH to give N and HCl 2 32 (4) Br2 reacts with hot and strong NaOH solution to given NaBr, NaBrO4 and H2O 5 . In XeF2, XeF4, XeF6 the number of lone pairs on Xe is respectively : [AIEEE-2002] (1) 2,3,1 (2) 1,2,3 (3) 4, 1, 2 (4) 3,2,1 6 . What may be expected when phosphine gas is mixed with chlorine gas: [AIEEE-2003] (1) PCl and HCl are formed and mixture cools down 5 (2) PH .Cl is formed with warming up 32 (3) The mixture only cools down (4) PCl and HCl are formed and the mixture warms up 3 7 . For making good quality mirrors, plates of float glass are used. These are obtained by floating molten glass over a liquid metal which does not solidify before glass. The metal used can be : [AIEEE-2003] (1) Sodium (2) Magnesium (3) Mercury (4) Tin 8 . Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite : [AIEEE-2003] (1) Has molecules of variable molecular masses like polymers (2) Has carbon atoms arranged in large plated of rings of strongly bonded carbon atoms with weak interplate bonds (3) Is a non crystalline substance (4) Is an allotropic form of diamond 9 . Concentrated hydrochloric acid when kept in open air sometimes produces a cloud of white fumes. This is due to : [AIEEE-2003] (1) Strong affinity of HCl gas for moisture in air results in forming of droplets of liquid solution which appears like a cloudy smoke (2) Due to strong affinity for water, conc. HCl pulls moisture of air towards self. The moisture forms droplets of water and hence the cloud (3) Conc. HCl emits strongly smelling HCl gas all the time (4) Oxygen in air reacts with emitted HCl gas to form a cloud of Cl gas 2 1 0 . Aluminium chloride exists as dimer, Al Cl in solid state as well as in solution of non-polar solvents such as 26 benzene. When dissolved in water, it gives- [AIEEE-2004] (1) Al3+ + 3Cl– (2) [Al(H O) ]3+ + 3Cl– (3) [Al(OH) ]3– + 3HCl 26 6 (4) Al O + 6HCl 23
1 1 . The soldiers of Napolean army while at Alps during freezing winter suffered a serious problem as regards to the tin buttons of their uniforms. White Metallic tin buttons get converted to grey powder. This transformation is related to:- [AIEEE-2004] (1) An interaction with water vapour contained in humid air (2) A change in crystalline structure of tin (3) A change in the partial pressure of O in air 2 (4) An interaction with N2 of air at low temperature 1 2 . Which one of the following statements regarding helium is incorrect [AIEEE-2004] (1) It is used to produce and sustain powerful superconducting magnets (2) It is used as a cryogenic agent for carrying out experiments at low temperatures (3) It is used to fill gas balloons instead of hydrogen because it is lighter then hydrogen and non-inflammable (4) It is used in gas-cooled nuclear reactors 1 3 . The structure of diborane contains [AIEEE- 2005] (1) Four 2c-2e bonds and four 3c-2e bonds (2) Two 2c-2e bonds and two 3c-2e bonds (3) Two 2c-2e bonds and four 3c-2e bonds (4) Four 2c-2e bonds and two 3c-2e bonds 1 4 . Heating an aqueous solution of aluminium chloride to dryness will give :- [AIEEE-2005] (1) AlCl (2) Al Cl (3) Al O (4) Al(OH)Cl 3 26 23 2 [AIEEE-2005] 1 5 . Which one of the following is the correct statement (1) Boric acid is a protonic acid (2) Beryllium exhibits coordination number of six (3) Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase (4) B H , 2NH is known as \"inorganic benzene\" 26 3 1 6 . In silicon dioxide : [AIEEE-2005] (1) Each silicon atom is surrounded by four oxygen atoms and each oxygen atom is bonded to two silicon atoms (2) Each silicon atom is surrounded by two oxygen atoms and each oxygen atom is bonded to two silicon atoms (3) Silicon atom is bonded to two oxygen atoms (4) There are double bonds between silicon and oxygen atoms 1 7 . The number of hydrogen atoms attached to phosphorus atom in hypophosphorous acid is : [AIEEE-2005] (1) Zero (2) Two (3) One (4) Three 1 8 . The correct order of the thermal stability of hydrogen halide (H-X) is : [AIEEE-2005] (1) HI > HBr > HCl > HF (2) HF > HCl > HBr > HI (3) HCl < HF > HBr < HI (4) HI > HCl < HF > HBr 1 9 . The stability of dihalides of Si, Ge, Sn and Pb increases steadily in the sequence: [AIEEE-2007] (1) GeX << SiX << SnX << PbX 22 2 2 (2) SiX << GeX << PbX << SnX 2 222 (3) SiX << GeX << SnX << PbX 2 222 (4) PbX << SnX << GeX << SiX 2 2 22
2 0 . Regular use of which of the following fertilizer increases the acidity of soil : [AIEEE-2007] (1) Potassium nitrate (2) Urea (3) Superphosphate of lime (4) Ammonium sulphate 2 1 . Four species are listed below : [AIEEE-2008] (i) HCO – (ii) H O+ (iii) HSO – (iv) HSO F 3 3 4 3 Which one of the following is the correct sequence of their acid strength? (1) iv < ii < iii < i (2) ii < iii < i < iv (3) i < iii < ii < iv (4) iii < i < iv < ii 2 2 . Among the following substituted silanes the one which will give rise to cross linked silicone polymer on hydrolysis is [AlEEE-2008] (1) R Si (2) RSiCl (3) R SiCl (4) R SiCl 4 3 22 3 2 3 . Which one of the following reactions of Xenon compounds is not feasible ? [AIEEE-2009] (1) 2XeF2 + 2H2O 2Xe + 4HF + O2 (2) XeF6 + RbF Rb[XeF7] (3) XeO3 + 6HF XeF6 + 3H2O (4) 3XeF4 + 6H2O 2Xe + XeO3 + 12HF + 1.5O2 2 4 . Boron cannot form which one of the following anions ? [AIEEE-2011] (1) B(OH)4– (2) BO2– (3) BF63– (4) BH4– 2 5 . In view of the signs of rG° for the following reactions [AIEEE-2011] PbO2 + Pb 2 PbO, rG° < 0 SnO2 + Sn 2 SnO, rG° > 0, Which oxidation states are more characteristic for lead and tin ? (1) For lead + 4, for tin + 2 (2) For lead + 2, for tin + 2 (3) For lead + 4, for tin + 4 (4) For lead + 2, for tin + 4 [AIEEE-2011] 2 6 . Which of the following statement is wrong ? (1) Single N–N bond is weaker than the single P–P bond (2) N2O4 has two resonance structures (3) The stability of hydrides increases from NH3 to BiH3 in group 15 of the periodic table (4) Nitrogen cannot form d-p bond 2 7 . Which of the following statements regarding sulphur is incorrect ? [AIEEE-2011] (1) At 600°C the gas mainly consists of S2 molceules (2) The oxidation state of sulphur is never less than +4 in its compounds (3) S2 molecule is paramagnetic (4) The vapour at 200°C consists mostly of S8 rings PREVIOUS YEARS QUESTIONS ANSWER KEY EXERCISE -5[A] Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans 2 1 4 4 4 1 3 2 3 2 2 3 4 3 3 Que. 16 17 18 19 20 21 22 23 24 25 26 27 Ans 1 2 2 3 4 3 2 3 3 4 3 2
EXERCISE–05 [B] PREVIOUS YEARS QUESTIONS 1 . The number of P—O—P bonds in cyclic metaphosphoric acid is – [IIT-2000] (A) Zero (B) Two (C) Three (D) Four 2 . The correct order of acidic strength is – [IIT- 2000] (A) Cl2O7 > SO2 < P4O10 (B) CO2 > N2O5 > SO3 (C) Na2O > MgO > Al2O3 (D) K2O > CaO > MgO 3 . Amongst H2O, H2S, H2Se and H2Te, the one with the highest boiling point is – [IIT- 2000] (A) H2O because of hydrogen bonding (B) H2Te because of higher molecular weight (C) H2S because of hydrogen bonding (D) H2Se because of lower molecular weight. 4 . Ammonia can be dried by – [IIT- 2000] (A) Conc. H2SO4 (B) P4O10 (C) CaO (D) Anhydrous CaCl2 [REE 2000] 5 . Which of the following are hydrolysed – (A) NCl (B) BCl (C) CCl (D) SiCl 3 3 4 4 6 . The set with correct order of acidity is – [IIT- 2001] (A) HClO < HClO2 < HClO3 < HClO4 (B) HClO4 < HClO3 < HClO2 < HClO (C) HClO < HClO4 < HClO3 < HClO2 (D) HClO4 < HClO2 < HClO3 < HClO 7. The reaction, 3ClO– (aq) C lO – (aq) + 2Cl– (aq) is an example of – [IIT- 2001] 3 (A) Oxidation reaction (B) reduction reaction (C) Disproportionation reaction (D) Decomposition reaction 8 . The number of S–S bonds in sulphur trioxide trimer, (S3O9) is – [IIT- 2001] (A) Three (B) Two (C) One (D) Zero 9. Statement-I : Between SiCl4 and CCl4, only SiCl reacts with water [IIT- 2001] 4 Because : Statement-II : SiCl is ionic and CCl is covalent 44 (A) If both assertion and reason are correct and reason is the corect explanation of the assertion (B) If both assertion and reason are correct, but reason is not the correct explanation of the assertion (C) If assertion is correct, but reason is incorrect (D) If assertion is incorrect, but reason is correct. 1 0 . Specify the coordination geometry around and hybridisation of N and B atoms in a 1 : 1 complex of BF and 3 NH – [IIT 2001] 3 (A) N: tetrahedral sp3 ; B : tetrahedral sp3 (B) N: pyramidal sp3 ; B : pyramidal sp3 (C) N: pyramidal sp3 ; B : planar sp2 (D) N: pyramidal sp3 ; B : tetrahedral sp3 d 1 1 . Polyphosphates are used as water softening agents because they – [IIT- 2002] (A) Form soluble complexes with anionic species (B) Precipitate anionic species (C) Form soluble complexes with cationic species (D) Precipitate cationic species
12. Identify, the correct order of acidic strength of CO2, CuO, CaO, HO – [IIT- 2002] 2 (A) CaO < CuO < H2O < CO2 (B) H2O < CuO < CaO < CO2 (C) CaO < H2O < CuO < CO2 (D) H2O < CO2 < CaO < CuO 1 3 . Identify the correct order of solubility of Na S, CuS, and ZnS in aqueous medium – [IIT- 2002] 2 (A) CuS > ZnS > Na2S (B) ZnS > Na2S > Cus (C) Na2S > Cus > ZnS (D) Na2S > ZnS > CuS 1 4 . H3BO3 is – [IIT- 2002] (A) Monobasic acid and weak Lewis acid (B) Monobasic and weak Bronsted acid (C) Monobasic and strong Lewis acid (D) Tribasic and weak Bronsted acid 1 5 . (Me)2 SiCl2 on hydrolysis will produce – [IIT- 2003] [IIT- 2003] (A) (Me)2 Si(OH)2 (B) (Me)2 Si = O (C) [—O—(Me)2 Si—O—]n (D) Me2 SiCl(OH) 16. When I– is oxidised by MnO – in alkaline medium, I– converts into – 4 (A) IO – (B) I2 (C) IO – (D) IO – 3 4 1 7 . Which is the most thermodynamically stable allotropic form of phosphorus? [IIT- 2004] (A) Red (B) White (C) Black (D) Yellow 1 8 . Which of the following is not oxidised by O3? [IIT- 2005] (A) KI (B) FeSO4 (C) KMnO4 (D) K2MnO4 1 9 . Which blue-liquid is obtained on reacting equimolar amounts of two gases at – 30ºC ? [IIT- 2005] (A) N2O (B) N2O3 (C) N2O4 (D) N2O5 2 0 . Name of the structure of silicates in which three oxygen atoms of [SiO4]4– are shared is – [IIT- 2005] (A) Pyrosilicate (B) Sheet silicate (C) Linear chain silicate (D) Three dimensional silicate 2 1 . B(OH)3 + NaOH NaBO2 + Na[B(OH)4] + H2O how can this reaction is made to proceed in forward direction ? [IIT- 2006] (A) Addition of cis 1, 2 diol (B) Addition of borax (C) Addition of trans 1, 2 diol (D) Addition of Na2HPO4 2 2 . The percentage of p-character in the orbitals forming P–P bonds in P4 is – [IIT- 2007] (A) 25 (B) 33 (C) 50 (D) 75 2 3 . Among the following, the paramagnetic compound is – [IIT- 2007] (D) KO2 (A) Na2O2 (B) O3 (C) N2O [IIT-1998, 4 M] 2 4 . Draw the structure of a cyclic silicate, (Si3O9)6– with proper labelling – [IIT-1998, 2 M] 2 5 . Complete and balance the following chemical equations – [IIT- 1998, 2M] (i) P4O10 + PCl5 (ii) SnCl4 + C2H5Cl + Na 2 6 . Work out the following using chemical equations \"Chlorination of calcium hydroxide produces bleaching powder\"
2 7 . Hydrogen peroxide acts both as an oxidizing and as a reducing agent in alkaline solution towards certain first row transition metal ion. Illustrate both these properties of H2O2 using chemical equations – [IIT- 1998, 4 M] 2 8 . Give reasons for the following in one or two sentences only. [IIT- 1999] \"BeCl2 can be easily hydrolysed.\" 2 9 . In the contact process for industrial manufacture of sulphuric acid, some amount of sulphuric acid is used as a starting material. Explain briefly. What is the catalyst used in the oxidation of SO2? [IIT- 1998,4 M] 3 0 . Give an exapmle of oxidation of one halide by another halogen. Explain the feasibility of the reaction. [IIT- 2000] 3 1 . Write the balanced chemical equation for developing photographic films. [IIT- 2001] 3 2 . Draw the molecular structures of XeF2, XeF4 and XeO2F2, indicating the location of lone pair (s) of electrons. [IIT- 2000] 3 3 . Give reason [IIT- 2000] Why elemental nitrogen exists as a diatomic molecule whereas elemental phosphorus is a tetra atomic molecule. 3 4 . Compounds X on reduction with LiAlH4 gives a hydride Y containing 21.72% hydrogen alongwith other products. The compound Y reacts with air explosively resulting in boron trioxide. Identify X and Y. Give balanced reactions involved in the formation of Y and its reaction with air Draw the structure of Y. [IIT- 2001] 3 5 . Starting from SiCl4, prepare the following in steps not exceeding the number given in parenthesis (reactions only) [IIT- 2001] (i) Silicon (1) (ii) Linear silicon containing methyl group only (4) (iii) Na2SiO3 (3) 3 6 . Identify (X) in the following synthetic scheme and write their structures. [IIT- 2001] BaC*O3 + H2SO4 X (gas) (C* denotes C14) 3 7 . Write the balanced equations for the reactions of the following compounds with water: [IIT- 2002] (i) Al4C3 (ii) CaNCN (iii) BF3 (iv) NCl3 (v) XeF4 3 8 . Identify the following: Na2CO3 SO2A Na2CO3B elemental SC I2D [IIT- 2003] (aq) Also mention the oxidation state of S in all the compounds. 3 9 . Arrange the following oxides in the increasing order of Bronsted basicity. [IIT- 2004] Cl2O7, BaO,SO3, CO2, B2O3 [IIT- 2003] MATCH THE COLUMN 4 0 . Column-I Column-II (A) Bi3+ BiO)+ (p) Heat (q) Hydrolysis (B) [AlO ]– Al(OH) (r) Acidification 2 3 (s) Dilution by water (C) SiO 4 Si O 6 4 7 2 (D) ( B O 2 ) [Bi(OH) ] 7 3 4
4 1 . Statement-I : In water, orthoboxric acid behaves as a weak monobasic acid. [IIT- 2007] Because : Statement-II : In water, orthoboric acid acts as a proton donor. (A) Statement-I is True, Statement-II is True; Statement-II is a 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 flase (D) Statement-I is False, Statement-II is True. Comprehension # 1 (Q-42, 43, 44) The noble gases have closed-shell electronic configuration and are monoatomic gases under normal conditions. The low boiling point of the lighter noble gases are due to weak dispersion forces between the atoms and the absence of other interatomic interactions. The direct reaction of xenon with fluorine leads to a series of compounds with oxidation number + 2, + 4 and + 6. XeF reacts violently with water to give XeO . The 43 compounds of xenon exhibit rich stereochemistry and their geometries can be deduced considering the total number of electron pairs in the valence shell. [IIT- 2007] 4 2 . Argon is used in arc welding because of its – (A) Low reactivity with metal (B) Ability to lower the melting point of metal (C) Flammability (D) High calorific value 4 3 . The structure of XeO3 is – (A) Linear (B) Planar (C) Pyramidal (D) T-shaped 4 4 . XeF4 and XeF6 are expected to be – (A) Oxidising (B) Reducing (C) Unreactive (D) Strongly basic Comprehension # 2 (Q-45, 46, 47) There are some deposits of nitrates and phosphates in earth’s crust. Nitrates are more soluble in water. Nitrates are difficult to reduce under the laboratory conditions but microbes do it easily. Ammonia forms large number of complexes with transition metal ions. Hybridization easily explains the ease of sigma donation capability of NH and PH . Phosphine is a flammable gas and is prepared from white phosphorous. 33 [IIT- 2008] 4 5 . Among the following, the correct statement is :- (A) Phosphates have no biological significance in humans (B) Between nitrates and phosphates, phosphates are less abundant in earth’s crust (C) Between nitrates and phosphates, nitrates are less abundant in earth’s crust (D) Oxidation of nitrates is possible in soil 4 6 . Among the following, the correct statement is :- (A) Between NH and PH , NH is a better electron donor because the lone pair of electrons occupies 3 33 spherical ‘s’ orbital and is less directional (B) Between NH and PH , PH is a better electron donor because the lone pair of electrons occupies 3 33 sp3 orbital and is more directional (C) Between NH and PH , NH is a better electron donor because the lone pair of electrons occupiessp3 3 33 orbital and is more directional (D) Between NH and PH . PH is a better electron donor because the lone pair of electrons occupies 3 33 spherical ‘s’ orbital and is less directional.
4 7 . White phosphorus on reaction with NaOH gives PH as one of the products. This is a :- 3 (A) dimerization reaction (B) disproportionation reaction (C) condensation reaction (D) precipitation reaction 4 8 . The reaction of P with X leads selectively to P O . The X is [JEE 2009] 4 46 (A) Dry O (B) A mixture of O , and N 2 22 (C) Moist O (D) O in the presence of aqueous NaOH 2 2 4 9 . The nitrogen oxide(s) that contain(s) N–N bond(s) is (are) [JEE 2009] (A) N O (B) N O (C) N O (D) N O 2 23 24 25 5 0 . In the reaction [JEE 2009] 2X + BH [BH (X) ]+[BH ]– 26 22 4 the amine(s) X is (are) (A) NH (B) CH NH (C) (CH ) NH (D) (CH ) N 3 32 32 33 51 . The reaction of white phosphorus with aqueous NaOH gives phosphine along with another phosphorus containing compound. The reaction type ; the oxidation states of phosphorus in phosphine and the other product are respectively [JEE 2012] (A) redox reaction ; -3 and –5 (B) redox reaction ; +3 and +5 (C) disproportionation reaction ; -3 and +1 (D) disproportionation reaction ; -3 and +3 5 2 . Bleaching powder contains a salt of an oxoacid as one of its components. The anhydride of that oxoacid is : [JEE 2012] (A) Cl O (B) Cl O (C) ClO (D) Cl O 2 27 2 26 5 3 . With respect to graphite and diamond, which of the statement(s) given below is (are) correct ? (A) Graphite is harder than diamond. [JEE 2012] (B) Graphite has higher electrical conductivity than diamond. (C) Graphite has higher thermal conductivity than diamond. (D) Graphite has higher C–C bond order than diamond.
PREVIOUS YEARS QUESTIONS ANSWER KEY EXERCISE -5[B] 1. C 2. A 3. A 4. C 5. B,D 6. A 7. C 8. D 9. C 10. A 11. C 12. A 13. D 14.A 15. C 16.A 17.C 18.C 19.B 20.B 21.A 22. D 23. D 2 4 . In cyclic (Si3O9)6–, three tetrahedral of SiO4 are joined together by sharing of two oxygen atoms per tetrahedral. Structure of (Si 3 O 6 ) 9 ·In it dark circles ( ) represent Si and open circles (O) represent oxygen atom or iron. 2 5 . (i) P4O10 + 6PCl3 10POCl3 (ii) SnCl4 + 2C2H5Cl + 2Na Na2SnCl6 + C4H10 2 6 . 3Ca(OH)2 + 2Cl2 Ca(OCl)2 + Ca(OH)2 CaCl2 · 2H2O Bleaching powder is a mixture of CaOCl2 and hydrated basic calcium chloride. 2 7 . When H2O2 acts as oxidizing agent, therefore, following reaction takes place: H2O2 + 2e– 2OH– while, regarding is action on reducing agent, the following reaction takes place : H2O2 + 2OH– O2 + 2H2O + 2e– Oxidizing character : 2Cr(OH)3 + 4NaOH + 3H2O2 2Na2CrO4 + 8H2O Reducing character: 2K3 [Fe(CN)6] + 2KOH + H2O2 2K4 [Fe(CN)6] + 2H2O + O2 2 8 . BeCl2 is hydrolysed due to high polarising power and presence of vacant p-orbitals in Be atom. (Be = 1s2, 2s2, 2p1x , 2p0y , 2p0z ) 2 9 . In SO3 + H2O H2SO4 reaction, H2SO4 is obtained in misty form and reaction is explosive (highly exothermic). By adding H2SO4 the above reaction is prevented. H2SO4 + SO3 H2S2O7 (oleum) H2S2O7 + H2O 2H2SO4 The catalyst used is V2O5 and K2O is used as promotor for the oxidation of SO2 into SO3. 3 0 . 2I– (aqueous) + Cl2 I2 + 2Cl– (aqueous) (i) 2I– (aqueous) I2 (s) + 2e– (ii) Cl2 (g) + 2e– 2Cl– (aq) Thus, I– is oxidised into I2 by Cl2 due to higher oxidised potential of Cl2 than I2
3 1 . Unreacted AgBr is removed by hypo (Na2S2O3) AgBr + 2Na2S2O3 Na3[Ag(S2O3)2] + NaBr 32. F Xe F In it Xe is sp3d-hybrid but its shape is linear due to involvent of VSEPR theory. (i.e., due to presence of three free pair of electrons, geometry of XeF2 is distorted from trigonal bipyramidal to linear). FF Xe FF In it Xe is sp3d2-hybrid but its shape is square planar due to involvement of VSEPR theory. (i.e., due to presence of two free pair of electrons, geometry of XeF4 is distorted from octahedral to square planer). F Xe F OO In it Xe is sp3 d-hybrid but its geometry is planar due to involvement of VSEPR theory. (i.e., due to presence of a free pair of electron, its geometry is distorted from trigonal bipyramidal to planar). 3 3 . In nitrogen, d-orbitals are not present, so in it the possiblity of intramolecular multiplicity exists which leads to the completion of octet through -bond between two nitrogen atoms. In phosphorus, d-orbitals are present, so in it due to large size of P, the P–P bonds are longer and hence intramolecular multiplicity is ruled out. So, for the completion of octet, it forms the bonds with three other 'P' atoms. Hence due to this reason it shows molecular formula as P4. 3 4 . X : BCl3 Y : B2H6 4BCl3 + 3LiAlH4 3AlCl3 + 3LiCl + 2B2H6 X B2H6 + 3O2 B2O3 + 3H2O (exothermic) Y 3 5 . (i) 3 SiCl4 + 4Al 3Si + 4AlCl3 (in one step) (ii) SiCl4 + 2Mg 2MgCl2 + Si Si + Cu Si – Cu 2CH3Cl + Si– Cu (CH3)2 SiCl2 + Cu (CH3)2SiCl2 + 2H2O (CH3)2Si(OH)2 + 2HCl
CH3 CH3 2(CH3)2Si(OH)2 H—O— Si —O— Si —OH –H2O CH3 CH3 (iii) SiCl4 + 4H2O Si(OH)4 + 4HCl Si(OH)4 SiO2 + 2H2O SiO2 + Na2CO3 Na2SiO3 + CO2 1673K 36. 14CO2 3 7 . (i) Al4C3 + 12H2O 4Al(OH)3 + 3CH4 (ii) CaNCN + 3H2O CaCO3 + 2NH3 (iii) BF3 + 3H2O H3BO3 + 3HF 3HF + 3BF3 3HBF4 4BF3 + 3H2O H3BO3 + 3HBF4 3 8 . Oxidation state (A) : NaHSO3 +4 (B) : Na2SO3 +4 (C) : Na2S2O3 +2 (D) : Na2S4O6 + 2.5 3 9 . Cl2O7 < SO3 < CO2 < B2O3 < BaO 4 0 . Thus, Q and R (A) : Bi3+ + H2O BiO+ + 2H+ thus ((Q) and S) (B) : A lO + H3O+ Al(OH)3 thus (R) 2 (C) : 2 SiO 4 + 2H+ Si2 O76 thus (R) 4 (D) : B4 O72 H B(OH)3 B 4 O27 H2O B(OH)3 Thus, (Q) and (R) 41. (C) Comprehension # 1 42.. (A) 43. (C) 44. (A) Comprehension # 2 47. (B) 50. (B, C) 45. (C) 46. (C) 53. (B, D) 48. (B) 49. (A, B, C) 51. (C) 52. (A)
EXERCISE - 01 CHECK YOUR GRASP SELECT THE CORRECT ALTERNATIVE (ONLY ONE CORRECT ANSWER) 1 . All samples of carbon dioxide contain carbon and oxygen in the mass ratio of 3 : 8. This is in agreement with the law of : (A) conservation of mass (B) constant proportion (C) multiple proportions (D) gaseous volumes 2 . That the atom is indivisible was proposed by : (A) Ruterford (B) Dalton (C) Bohr (D) Einstein 3 . Atomic mass of an element is : (A) actual mass of one atom of the element (B) relative mass of an atom of the element (C) average relative mass of different atoms of the element (D) always a whole number 4 . Which of the following expressions is correct (n = no. of moles of the gas, N = Avogadro constant, A m = mass of 1 molecule of the gas, N = no. of molecules of the gas) ? (A) n = mN (B) m = N (C) N = nN (D) m = n/N A A A A 5 . The volume of 1 mol of a gas at standard temperature and pressure is : (A) 11.2 litres (B) 22.4 litres (C) 100 litres (D) none of these 6 . The charge on 1 gram ions of Al3+ is : (A) 1 Ne coulomb 1 1 (D) 3 × N e coulomb A (B) × N e coulomb (C) × N e coulomb A 27 3A 9A 7 . In which of the following pairs do 1 g of each have an equal number of molecules : (A) N O and CO (B) N and C O (C) N and CO (D) N O and C O 2 2 32 2 22 8 . A quantity of aluminium has a mass of 54.0 g. What is the mass of the same number of magnesium atoms ? (At. wt. Al = 27, Mg = 24) (A) 12.1 g (B) 23.3 g (C) 48 g (D) 97.2 g 9 . Which of the following samples contains the largest number of atoms ? (A) 1 g of Ni(s) (B) 1 g of Ca(s) (C) 1 g of N (g) (D) 1 g of B(s) 2 1 0 . Which of the following contains greatest number of oxygen atoms : (A) 1 g of O (B) 1 g of O 2 (C) 1 g of O (D) all have the same number of atoms 3 1 1 . A sample of ammonium phosphate, (NH ) PO , contains 3.18 mol of hydrogen atoms. The number of 43 4 moles of oxygen atoms in the sample is : (A) 0.265 (B) 0.795 (C) 1.06 (D) 3.18 1 2 . How many moles of electron weigh one kilogram : (A) 6.023 × 1023 (B) 1 1031 (C) 6.023 1054 (D) 1 108 9.108 9.108 9.108 6.023 1 3 . A compounds was found to contain 5.37% nitrogen. What is the minimum molecular wt. of compound : (A) 26.07 g (B) 2.607 (C) 260.7 (D) none
1 4 . Under the same conditions, two gases have the same number of molecule. They must : (A) be noble gases (B) have equal volumes (C) have a volume of 22.4 dm3 each (D) have an equal number of atoms 1 5 . Four 1 litre flasks are separately filled with the gases H , He, O and O at the same temperature and pressure. 2 23 The ratio of total number of atoms of these gases present in different flask would be : (A) 1 : 1 : 1 : 1 (B) 1 : 2 : 2 : 3 (C) 2 : 1 : 2 : 3 (D) 3 : 2 : 2 : 1 1 6 . The atomic weight of Cu is 63.546. There are only two naturally occurring isotopes of copper 63Cu and 65Cu. The natural abundance of the 63Cu isotope must be approximately : (A) 10% (B) 30% (C) 50% (D) 70% 1 7 . If the percentage of water of crystallization in MgSO .x H O is 13%. What is the value of x : 42 (A) 1 (B) 4 (C) 5 (D) 7 1 8 . A pure gas that is 14.3% hydrogen and 85.7% carbon by mass has a density of 2.5 g L–1 at 0°C and 1 atm pressure. What is the molecular formula of the gas : (A) CH (B) C H (C) C H (D) C H 2 24 48 6 12 1 9 . A certain alkaloid has 70.8% carbon, 6.2% hydrogen, 4.1% nitrogen and the rest oxygen. What is its empirical formula : (A) C H NO (B) C H NO 4 (C) C H NO (D) C H NO 20 21 4 20 20 21 20 3 20 19 3 2 0 . The empirical formula of a compound of molecular mass 120 is CH O. The molecular formula of the 2 compound is : (A) C2H4O2 (B) C4H8O4 (C) C3H6O3 (D) all of these 2 1 . 0.250 g of an element M, reacts with excess fluorine to produce 0.547 g of the hexafluoride MF . What 6 is the element : [Cr = 52, Mo = 96, S = 32, Te = 127.6] (A) Cr (B) Mo (C) S (D) Te 2 2 . A 1000 gram sample of NaOH contains 3 moles of O atoms, what is the % purity of NaOH : (A) 14% (B) 100% (C) 12% (D) 24% 2 3 . A 15 mL sample of 0.20 M MgCl is added to 45 mL of 0.40 M AlCl , What is the molarity of 23 Cl–ions in the final solution: (A) 1.0 M (B) 0.60 M (C) 0.35 M (D) 0.30 M 2 4 . Mole fraction of ethanol in ethanol and water mixture is 0.25. Hence percentage concentration of ethanol by weight of mixture is : (A) 25% (B) 75% (C) 46% (D) 54% 2 5 . How many moles of Na+ ions are in 20 mL of 0.40 M Na PO : 34 (A) 0.0080 (B) 0.024 (C) 0.050 (D) 0.20 2 6 . Out of Molarity (M), Molality (m), Formality (F) and Mole fraction (x), those independent of temperature are : (A) M,m (B) F,x (C) m,x (D) M,x 2 7 . The molality of a 1 L solution with x % H SO is 9. The weight of solvent present in the solution is 910 24 grams. The value of x is : (A) 90 (B) 80.3 (C) 30.38 (D) 46.87 2 8 . Density of ozone relative to oxygen is under the same temperature & pressure : (A) 1 (B) 2 (C) 1.5 (D) 2.5
2 9 . Mole fraction of A in H O is 0.2. The molality of A in H O is : 22 (A) 13.8 (B) 15.5 (C) 14.5 (D) 16.8 3 0 . The molarity of the solution containing 2.8% mass-volume solution of KOH/(Given atomic mass of K = 39) is : (A) 0.1 M (B) 0.5 M (C) 0.2 M (D) 1 M 3 1 . The molality of a sulphuric acid solution is 0.2 mol/kg. Calculate the total weight of the solution : (A) 1000 g (B) 1098.6 g (C) 980.4 g (D) 1019.6 g 3 2 . What volume of a 0.8 M solution contains 100 millimoles of the solute : (A) 100 mL (B) 125 mL (C) 500 mL (D) 62.5 mL 3 3 . 500 mL of a glucose solution contains 6.02 × 1022 molecules. The concentration of the solution is : (A) 0.1 M (B) 1.0 M (C) 0.2 M (D) 2.0 M 3 4 . 50 mL of CO is mixed with 20 mL of oxygen and sparked, After the reaction, the mixture is treated with an aqueous KOH solution. Choose the correct option : (A) the volume of CO that reacts = 30 mL (B) volume of CO formed = 50 mL 2 (C) volume of CO that remains after treatment with KOH = 10 mL (D) the volume of the CO that remains after treatment with KOH = 20 mL CHECK YOUR GRASP ANSWER KEY EXERCISE -1 Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans . B B C C B D C C D D C D C B C Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans . D A C A B B C A C B C D C A B Que. 31 32 33 34 Ans . D B C C
EXERCISE–02 BRAIN TEASERS SELECT THE CORRECT ALTERNATIVES (ONE OR MORE THEN ONE CORRECT ANSWERS) 1 . An alloy of gold and silver contains 38.5% silver by mass and has a density of 14.6 g.mL–1. What is the molar concentration of silver in this alloy : (A) 52.1 mol.L–1 (B) 45.6 mol.L–1 (C) 3.57 mol.L–1 (D) 2.64 mol.L–1 2 . \"Suvarnabhasm\", an ayurvedic drug, is found to contain 400 ppm of colloidal gold. Mass % of gold (atomic mass of Au = 197) will be : (A) 0.040 % (B) 7.88 % (C) 0.0788 % (D) 4 × 10–4 % 3 . A solution containing 12.0% sodium hydroxide by mass has a density of 1.131 g/mL. What volume of this solution contains 5.00 mol of NaOH : (A) 0.0240 L (B) 1.67 L (C) 1.47 L (D) 1.00 L 4 . An aqueous solution of concentrated hydrobromic acid contains 48% HBr by mass. If the density of the solution is 1.50 g / mL, what is its concentration : (A) 11.4 mol/L (B) 8.9 mol/L (C) 5.9 mol/L (D) 18.5 mol/L 5 . An antifreeze mixture consists of 40% ethylene glycol (C2H6O2) by weight in aqueous solution. If the density of this solution is 1.05 g/mL, what is the molar concentration : (A) 6.77 M (B) 6.45 M (C) 0.017 M (D) 16.9 M 6 . What is the molality m, of methanol in a solution prepared by dissolving 160 g of methanol, CH OH, 3 in 200.0 g of water : (A) 1.0 m (B) 5.0 m (C) 10.0 m (D) 25.0 m 7 . XeF fluorinates I to IF and liberates Xenon (g). 210 mmol of XeF can yield a maximum of __ mmol 6 27 6 of lF : 7 (A) 420 (B) 180 (C) 210 (D) 245 8 . When 100 g of ethylene polymerises entirely to polyethene, the weight of polyethene formed as per the equation nCH = CH (CH – CH )n is : 2 2 2 2 (A) (n/2)g (B) 100g (C) (100/n)g (D) 100n g 9 . A 10 gram sample of natural gas containing CH and C H was burnt in excess of oxygen to give 29.0 4 24 grams of CO2 and some water. How many grams of water are formed : (A) 9.42 g (B) 18.81 g (C) 11.42 g (D) 15.31 g 1 0 . 50 g of ZnS are strongly heated in air to effect partial oxidation and the resultant mass weighed 44 g. What is the ratio of ZnO to ZnS in the resultant mixture : (A) 13.5 : 30.5 (B) 27 : 12.58 (C) 27 : 15.31 (D) 30.52 :13.48 1 1 . The % loss in weight after heating a pure sample of potassium chlorate (M. wt. 122.5) will be : (A) 12.25 (B) 24.50 (C) 39.17 (D) 49.0 1 2 . In a gaseous reaction of the type aA + bB cC + dD, which is wrong : (A) a litre of A combines with b litre of B to give C & D (B) a mole of A combines with b mole of B to give C & D (C) a g of A combines with b g litre of B to give C & D (D) a molecules of A combines with b molecule of B to give C & D
1 3 . Iodobenzene (C H I) is prepared from aniline (C H NH ) in a two step process as shown below 65 65 2 C H NH + HNO + HCl C H N +Cl– + 2H O CHN +Cl– + KI C HI+ N+ KCl 65 2 2 6 52 2 6 52 65 2 In an actual preparation 9.30 g of aniline was converted to 16.32 g of iodobenzene. The percentage yield of iodobenzene is : (A) 8 % (B) 50 % (C) 75 % (D) 80 % 1 4 . In an organic compound of molar mass greater than 100 containing only C, H and N, the percentage of C is 6 times the percentage of H while the sum of the percentages of C and H is 1.5 times the percentage of N. What is the least molar mass : (A) 175 (B) 140 (C) 105 (D) 210 1 5 . The simplest formula of a compound containing 50% of element X (atomic mass = 10) and 50% of the element Y (atomic mass = 20) by weight is : (A) XY (B) X Y (C) XY (D) X Y 2 2 23 1 6 . The sodium salt of methyl orange has 7% sodium. What is the minimum molecular weight of the compound? : (A) 420 (B) 375 (C) 329 (D) 295 1 7 . In the preceding problem, if the compound contains 12.8% nitrogen 9.8% sulphur how many nitrogen and sulphur atoms are present per atom of sodium : (A) 2 and 1 (B) 1 and 3 (C) 1 and 2 (D) 3 and 1 1 8 . How many grams of urea on heating yield 1022 molecules of biuret by the reaction : 2 CO (NH ) HN - CO - NH - CO - NH + NH ? 22 2 2 3 (A) 1.495 (B) 0.995 (C) 1.99 (D) 1.753 1 9 . A certain compound has the molecular formula X O . If 10 g of X O has 5.72 g of X, atomic mass of 46 46 X is : (A) 32 amu (B) 37 amu (C) 42 amu (D) 98 amu 2 0 . DNA has density 1.1 g/mL and its molecular weight is 6 × 103 g/mol. Average volume occupied by its single molecule will be : (A) 9.1 × 10–20 cc (B) 9.1 × 10–21 cc (C) 9.8 × 10–21 cc (D) 9.6 × 10–20 cc 2 1 . For an infinitely dilute aqueous solution molality will be equal to : (A) formality (B) molarity (C) mole fraction (D) ppm 2 2 . If 1 g of HCl and 1 g of MnO heated together the maximum weight of Cl gas evolved will be : 22 [MnO + 4HCl MnCl + Cl + 2H O] : 2 2 2 2 (A) 2 g (B) 0.975 g (C) 0.486 g (D) 0.972 g 2 3 . Molarity of H SO is 18 M. Its density is 1.8 g/cm3, hence molality is : 24 (A) 18 (B) 100 (C) 36 (D) 500 24. If 11 moles of oxygen combine with Al to form Al O , the weight of Al used in the reaction is (Al = 27): 2 23 (A) 27 g (B) 54 g (C) 40.5 g (D) 81 g (C) 6 (D) 8 2 5 . Na SO . xH O has 50% H O. Hence, x is : 24 2 2 (A) 4 (B) 5
2 6 . Cortisone is a molecular substance containing 21 atoms of carbon per molecule. The mass percentage of carbon in cortisone is 69.98 %. Its molar mass is : (A) 176.5 (B) 252.2 (C) 287.6 (D) 360.1 2 7 . A spherical ball of radius 7 cm contains 56% iron. If density is 1.4 g/cm3, number of mol of Fe present approximately is : (A) 10 (B) 15 (C) 20 (D) 25 2 8 . In the following final result is ....0.1 mol CH + 3.01 × 1023 molecules CH – 9.6 g CH = x mol H atoms : 4 44 (A) 0 mol H atom (B) 0.2 mol H atom (C) 0.3 mol H atom (D) 0.4 mol H atom 2 9 . The density of 2.45 M aqueous methanol (CH OH) is 0.976 g/mL. What is the molality of the solution 3 (CH OH = 32) ? 3 (A) 27.3 m (B) 0.273 m (C) 7.23 m (D) 2.73 m 3 0 . Equal volumes of 10% (v/v) of HCl is mixed with 10% (v/v) NaOH solution. If density of pure NaOH is 1.5 times that of pure HCl then the resultant solution be ? (A) basic (B) neutral (C) acidic (D) can't be predicted. 3 1 . A definite amount of gaseous hydrocarbon having (carbon atoms less than 5) was burnt with sufficient amount of O . The volume of all reactants was 600 mL, after the explosion the volume of the products [CO (g) 22 and H2O (g)] was found to be 700 mL under the similar conditions. The molecular formula of the compound is ? (A) C H (B) C H (C) C H (D) C H 38 36 34 4 10 3 2 . What is the molar mass of diacidic organic Lewis base, if 12 g of chloroplatinate salt on ignition produced 5 g residue ? (A) 52 (B) 58 (C) 88 (D) none of these 3 3 . Solutions containing 23 g HCOOH is/are : w (A) 46 g of 70% HCOOH (d = 1.40 g/mL) v solution (B) 50 g of 10 M HCOOH (d = 1 g/mL) solution w (C) 50 g of 25% w HCOOH (D) 46 g of 5 M HCOOH (dsolution = 1 g/mL) 3 4 . A sample of H O solution labelled as \"28 volume\" has density of 265 g/L. Mark the correct option(s) 22 representing concentration of same solution in other units : (A) M H2O2 2.5 (B) % w 17 (C) mole fraction of H O = 0.2 v 22 (D) m H2O2 13.88 BRAIN TEASERS ANSWER KEY EXERCISE -2 Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans. A A C B A D B B B D C C D B B Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans. C D C A B B C D B D D C A D A Que. 31 32 33 34 Ans. A B A,B A,C,D
EXERCISE–03 MISCELLANEOUS TYPE QUESTIONS TRUE / FALSE 1 . Two elements always combine together in a fixed ratio by weight. 2 . There is no difference between one mole and one gram molecule. 3 . Equal volumes of different gases under similar conditions of temperature and pressure contain equal number of atoms. 4 . Empirical formula represents the actual number of atoms present in a molecule of the substance. 5 . A balanced equation contains equal number of atoms of each element on both sides of the equation. 6 . Mass of reactants is always equal to the mass of the products. FILL IN THE BLANKS 1 . Law of conservation of mass was put forward by ................... . 2 . The formation SO2 and SO3 illustrates the law of ................... . 3 . The number of atoms present in one molecule of an elementary substance is called its ................... . 4 . The mass of an atom of carbon is ................... . 5 . The reactant which reacts completely in a reaction is called ................... . 6 . According to Dulong and Petit's law, Atomic wt. × Specific heat = .................... (approx) 7 . The Sl unit of density is ................... . MATCH THE COLUMN 1. Column-I Column-II (A) Law of conservation of mass (B) Law of multiple proportion (p) CH has carbon and hydrogen in 3 : 1 mass ratio. (C) Law of definite proportion 4 (D) Law of reciprocal proportion (q) 10 mL N combines with 30 mL of H to form (E) Gay Lussac's Law 22 20 mL of NH 3 (r) S and O combine to form SO and SO 2 23 (s) In H S and SO mass ratio of H and O w.r.t. sulphur 22 is 1 : 16, hence in H2O, mass ratio of H and O is 1 : 8. (t) 4.2 g MgCO gives 2.0 g residue on heating. 3 2. Column-I Column-II (mass of product) (A) 2H + O 2H2O (p) 1.028 g 2 2 (q) 1.333 g 1g 1g (r) 1.125 g (B) 3H + N 2NH3 2 2 (s) 1.214 g 1g 1g (C) H + Cl 2HCl 2 2 1g 1g (D) 2H + C CH4 2 1g 1g
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 : 16 g each O and O contains NA and NA atoms respectively. 23 23 Because Statement-II : 16 g O and O contains same no. of atoms. 23 2 . Statement-I : 44 g of CO , 28 g of CO have same volume at STP. 2 Because Statement-II : Both CO and CO are formed by C and oxygen. 2 3 . Statement-I : Law of conservation of mass hold good for nuclear reaction. Because Statement-II : Law states that mass can be neither created nor destroyed in a chemical reaction. 4 . Statement-I : A reactant that is entirely consumed when a reaction goes to completion is known as limiting reactant. Because Statement-II : The amount of reactant limits the amount of product formed. 5 . Statement-I : The balancing of chemical equations is based on law of conservation of mass. Because Statement-II : Total mass of reactants is equal to total mass of products. 6 . Statement-I : Pure water obtained from different sources such as, river, well, spring, sea etc. always contains hydrogen and oxygen combined in the ratio 1 : 8 by mass. Because Statement-II : A chemical compound always contains elements combined together in same proportion by mass, it was discovered by French chemist, Joseph Proust (1799). 7 . Statement-I : The percentage weight of a compound A in a solution is given by % of A = Mass A × 100 Total mass of solution Because Statement-II : The mole fraction of a component A is given by, No. of moles of A Mole fraction of A = Total no. of moles of all components 8 . Statement-I : A one molal solution prepared at 20°C will retain the same molality at 100°C, provided there is no loss of solute or solvent on heating. Because Statement-II : Molality is independent of temperature. 9 . Statement-I : The molality and molarity of dilute aqueous solutions differ very little. Because Statement-II : The density of water is 1.0 g cm–3 at room temperature. 1 0 . Statement-I : The average mass of one Mg atom is 24.305 amu, which is not the actual mass of one Mg atom. Because Statement-II : Three isotopes, 24Mg, 25Mg and 26Mg, of Mg are found in nature.
1 1 . Statement-I : A molecule of butane, C H has a mass of 58.12 amu. 4 10 Because Statement-II : One mole of butane contains 6.022 × 1023 molecules and has a mass of 58.12 g. 1 2 . Statement-I : Both 12 g. of carbon and 27 g. of aluminium will have 6.02 × 1023 atoms. Because Statement-II : Gram atomic mass of an element contains Avogadro's number of atoms. COMPREHENSION BASED QUESTIONS Comprehension # 1 Potash is any potassium mineral that is used for its potassium content. Most of the potash produced in the United States goes into fertilizer. The major sources of potash are potassium chloride (KCl) and potassium sulphate (K2SO4). Potash production is often reported as the potassium oxide (K2O) equivalent or the amount of K2O that could be made from a given mineral. KCl costs Rs. 50 per kg. 1 . What is the cost of K per mole of the KCl sample? (A) Rs. 13.42 mol–1 (B) Rs. 3.73 mol–1 (C) Rs. 1.00 mol–1 (D) Rs. 2.00 mol–1 2 . For what price must K2SO4 be sold in order to supply the same amount of potassium as in KCl ? (A) Rs. 58.40 kg–1 (B) Rs. 50.00 kg–1 (C) Rs. 42.82 kg–1 (D) Rs. 25.00 kg–1 3 . What mass (in kg) of K2O contains the same number of moles of K atoms as 1.00 kg KCl? (A) 0.158 kg (B) 0.315 kg (C) 1.262 kg (D) 0.631 kg Comprehension # 2 Calcium lactate is used in the food and beverage industries. It has also been used medicinally for treatment of various allergies, for treatment of muscular leg cramps, and as an antidote for a variety of poisons, including lead, arsenicals and carbon tetrachloride. A 0.8274 g sample of anhydrous calcium lactate is found by analysis to contain 0.2732 g of C, 0.0382 g H, 0.1520 g Ca and 0.3640 g O. Each mole of calcium lactate is found to contain one mole of calcium ions. Calcium lactate can be crystallised from water as pentahydrate salt. 1 . Simplest formula of the calcium lactate is : (A) CaO6C6H10 (B) CaO3C3H5 (C) CaO2C3H3 (D) CaO2C3H5 2 . Formula weight of calcium lactate is : (A) 129 g mol–1 (B) 111 g mol–1 (C) 218 g mol–1 (D) 113 g mol–1 3 . How many grams of calcium lactate pentahydrate would be recovered from 1 g of anhydrous salt : (A) 1.41 g (B) 1.00 g (C) 1.27 g (D) 1.51 g Comprehension # 3 NaBr, used to produce AgBr for use in photography can be self prepared as follows : Fe + Br2 FeBr2 .....(i) FeBr + Br F e Br 8 .....(ii) (not balanced) 2 2 3 (not balanced) .....(iv) Fe3Br8 + Na2CO3 NaBr + CO2 + Fe3O4 .....(iii) How much Fe in kg is consumed to produce 2.06 × 103 kg NaBr 1 . Mass of iron required to produce 2.06 × 103 kg NaBr (A) 420 g (B) 420 kg (C) 4.2 × 105 kg (D) 4.2 × 108 g 2 . If the yield of (ii) is 60% & (iii) reaction is 70% then mass of iron required to produce 2.06 × 103 kg NaBr. (A) 105 kg (B) 105 g (C) 103 kg (D) none
3 . If yield of (iii) reaction is 90% then mole of CO2 formed when 2.06 × 103 kg NaBr is formed. (A) 20 (B) 10 (C) 40 (D) none Comprehension # 4 A monobasic acid of weight 15.5 g is heated with excess of oxygen & evolved gases when passed through KOH solution increased its weight by 22 g and when passed through anhydrous CaCl2, increased its weight by 13.5 g. When the same mass of this organic acid is reacted with excess of silver nitrate solution form 41.75 g silver salt of the acid which on ignition gave the residue of weight 27 g. 1 . The molecular formula of the organic acid is. (A) C2H6 (B) C2H5O2 (C) C2H6O2 (D) C2H4O 2 . The molar masses of the acid & its silver salt respectively are: (A) 60, 168 (B) 167, 60 (C) 60, 167 (D) 168, 60 Comprehension # 5 342 g of 20% by mass of Ba(OH)2 solution (sp. gr. 0.57) is reacted with 200 mL of 2 M HNO3 according to given balanced reaction : Ba(OH)2 + 2HNO3 Ba(NO3)2 + 2H2O 1 . The nature of the final solution is : (A) acidic (B) neutral (C) basic (D) can't say 2 . Find the molarity of the ion in resulting solution by which nature of the above solution is identified, is (A) 0.5 M (B) 0.8 M (C) 0.4 M (D) 1 M MISCELLANEOUS TYPE QUESTION ANSWER KEY EXERCISE -3 True / False 1. F 2. T 3. F 4. F 5. T 6. T Fill in the Blanks 1. Lavoisier 2. Multiple proportions 3. Atomicity 4. 1.99 × 10–23 g 5. Limiting reagent 6. kg m–3 7 . kg m–3 Match the Column 1. (A) t ; (B) r ; (C) p ; (D) s ; (E) q 2. (A) r ; (B) s ; (C) p ; (D) q Assertion - Reason Questions 1. D 2. B 3. D 4. A 5. A 6. A 7. B 8. A 9. A 10. A 11. A 12. A Comprehension Based Questions Comprehension # 1: 1. (B) 2. (C) 3. (D) 3. (A) Comprehension # 2: 3. (B) 1. (A) 2. (C) Comprehension # 3: 1. (B) 2. (C) Comprehension # 4: 1. (C) 2. (A) Comprehension # 5: 1. (C) 2. (A)
EXERCISE–04 [A] CONCEPTUAL SUBJECTIVE EXERCISE 1 . 1.375 g of cupric oxide was reduced by heating in a current of hydrogen and the weight of copper obtained was 1.098 g. In another experiment, 1.179 g of copper was dissolved in nitric acid and the resulting solution was evaporated to dryness. The residue of copper nitrate when strongly heated was converted into 1.4476 g of cupric oxide. Show that the results are in agreement with the law of constant pro- portion. 2 . Elements X and Y from two different compounds. In the first 0.324 g of X is combined with 0.471 g of Y. In second, 0.117 g of X is combined with 0.509 g of Y. Show that these data illustrate the law of multiple proportions. 3 . How many g of element are present in 35.125 g atom of Si. (Given at. wt. of Si = 28.) 4 . Calculate the no. of molecules in a drop of water weighing 0.07 g. 5 . Calculate no. of each atom present in 106.5 g of NaClO . 3 6 . Find the no. of mole of phosphorus in 92.9 g of phosphorus assuming that molecular formula of phos- phorus in P . Also determine the no. of atoms and molecules of phosphorus in the sample. 4 7 . Calculate the number of moles in 5.75 g of sodium. (Atomic mass of sodium = 23.) 8 . How many grams of each of the following elements must be taken to get 1 mol of the element? (a) Sodium (b) Chlorine (c) Copper 9 . The density of liquid mercury is 13.6 / cm3. How many moles of mercury are there in 1 litre of the metal ? (Atomic mass of Hg = 200) 1 0 . 50 g of CaCO is allowed to react with 70 g of H PO . Calculate : 3 34 (i) amount of Ca (PO ) formed (ii) amount of unreacted reagent 3 42 1 1 . N H , Hydrazine a rocket fuel can be produced according to the following reaction : 24 ClNH + 2NH N2H4 + NH Cl 2 3 4 When 1000 g ClNH is reacted with excess of NH , 473 g N H is produced. What is the % yield of the 2 3 24 reaction. 1 2 . Carbon disulphide 'CS ', can be made from by product SO . The overall reaction is 22 5C + 2SO CS + 4CO 22 How much CS can be produced from 450 kg of waste SO with excess of coke if the SO conversion 2 22 is 82%. 1 3 . Calculate the percent of BaO in 29.0 g of a mixture of BaO and CaO which just reacts with 100.8 mL of 6.00 M HCl. BaO + 2HCl BaCl2 + HO 2 CaO + 2HCl CaCl2 + HO 2 1 4 . Calculate the amount of 95% pure Na CO required to prepare 5 litre of 0.5 M solution. 23 1 5 . Calculate the molality of a sulphuric acid solution of specific gravity 1.2 containing 27% H SO by 24 weight. 1 6 . A gaseous alkane is exploded with oxygen. The moles of O for complete combustion and CO formed 22 is in the ratio 7 : 4. Deduce molecular formula of alkane. 1 7 . When 2.86 g of a mixture of 1-butene, C H and butane C H was burned in excess of oxygen, 48 4 10 8.80 g of CO and 4.14 g of H O were obtained. What is percentage by mass of butane in the mixture. 22
1 8 . If v mL of a gaseous hydrocarbon, after explosion with excess of oxygen, showed a contraction of 2.5 v mL and a further contraction of 2v mL with caustic potash, Find the formula of hydrocarbon. 1 9 . The average mass of one gold atom in a sample of naturally occuring gold is 3.2707 × 10–22 g. Use this to calculate the molar mass of gold. 2 0 . A plant virus is found to consist of uniform symmetrical particles of 150 Å in diameter and 5000 Å long. The specific volume of the virus is 0.75 cm3/g. If the virus is considered to be a single particle, find its molecular weight. 2 1 . Density of a gas relative to air is 1.17. Find the mol. mass of the gas [M = 29 g/mol] air 2 2 . One type of artificial diamond (commonly called YAG for yttrium aluminium garnet) can be represented by the formula Y Al O . 3 5 12 (a) Calculate the weight percentage composition of this compound. (b) What is the weight of yttrium present in a 200 – carat YAG if 1 carat - 200 mg ? (Y = 89, Al = 27) 2 3 . A chemical commonly called \"dioxin\" has been very much in the news in the past few years. (It is the by product of herbicide manufacture and is thought to be quite toxic.) Its formula is C H Cl O . If you 12 4 4 2 have a sample of dirt (28.3 g) that contains 1.0 × 10–4 % dioxin, how many moles of dioxin are in the dirt sample? 2 4 . A chemist wants to prepare diborane by the reaction 6 LiH + 8 BF 6 Li BF + BH 3 4 26 If the starts with 2.0 moles each of LiH & BF . How many moles B H can be prepared. 3 26 2 5 . One gram of an alloy of aluminium and magnesium when heated with excess of dil. HCl forms magnesium chloride, aluminium chloride and hydrogen. The evolved hydrogen collected over mercury at 0°C has a volume of 1.2 litres at 0.92 atm pressure. Calculate the composition of the alloy. 2 6 . A 10 g sample of a mixture of calcium chloride and sodium chloride is treated with Na CO to precipitate 23 calcium as calcium carbonate. This CaCO is heated to convert all the calcium to CaO and the final mass 3 of CaO is 1.62 g. Calculate % by mass of NaCl in the original mixture. 2 7 . By the reaction of carbon and oxygen, a mixture of CO and CO is obtained. What is the composition 2 of the mixture by mass obtained when 20 grams of O reacts with 12 grams of carbon ? 2 2 8 . The action of bacteria on meat and fish produces a poisonous compound called cadaverine. As its name and origin imply, it stinks ! It is 58.77% C, 13.81 % H, and 27.42 % N. Its molar mass is 102 g/mol. Determine the molecular formula of cadaverine. 2 9 . Given the following empirical formulae and molecular weight, compute the true molecular formulae : Empirical formula Molecular weight (a) CH 84 2 150 34 (b) CH O 2 (c) H O (d) HgCl 472 (e) HF 80 3 0 . What is the percentage of nitrogen in an organic compound 0.14 g of which gave by Dumas method 82.1 c.c. of nitrogen collected over water at 27°C and at a barometric pressure of 774.5 mm? (aqueous tension of water at 27°C is 14.5 mm)
3 1 . Calculate the molarity of the following solutions : (a) 4g of caustic soda is dissolved in 200 mL of the solution. (b) 5.3 g of anhydrous sodium carbonate is dissolved in 100 mL of solution. (c) 0.365 g of pure HCl gas is dissolved in 50 mL of solution. 3 2 . A mixture of ethanol and water contains 54 % water by mass. Calculate the mole fraction of alcohol in this solution. 3 3 . 10 mL of a mixture of CO, CH , and N exploded with excess of oxygen gave a contraction of 6.5 mL. 42 There was a further contraction of 7 mL, when the residual gas treated with KOH. What is the composition of the original mixture? 3 4 . When 100 mL of a O – O mixture was passed through turpentine, there was reduction of volume by 23 20 mL. If 100 mL of such a mixture is heated, what will be the increase in volume? CONCEPTUAL SUBJECTIVE EXERCISE ANSWER KEY EXERCISE-4(A) 3. 983.5 g of Si 4 . 2.34 × 1021 molecules of H O 2 5. 6.023 × 1023 atom Na, 6.023 × 1023 atom Cl, 18.06 × 1023 atom O 6. 0.75 mol, 4.52 × 1023 molecules P , 18.04 × 1023 atom P 4 7. 0.25 mol 8 . (a) 23 g (b) 35.5 g (c) 63.5 g 9. 68 1 0 . (i) 51.66 g (ii) 37.31 g 11. 76.12% 1 2 . 219.09 kg CS 13. 65.65% 1 4 . 278.94 g 15. 3.8 2 1 7 . 60.8 % 18. C H 19. 196.2 21 . 33.9 16. C H 26 26 2 0 . 7.09 × 107 22. (a) Y = 44.95%, Al = 22.73 %, O = 32.32% (b) 17.98 g 2 3 . 8.8 × 10–8 mol 24. 0.250 2 5 . Al = 0.546 g, Mg = 0.454g 26. 67.9% 27. CO : CO =21 : 11 28. C H N 2 9 . (a) C H (b) C H O (c) H O (d) Hg Cl (e) H F 2 5 14 2 6 12 5 10 5 22 22 44 30. 66.7 % 3 1 . (a) 0.5M, (b) 0.5 M, (c) 0.2 M 32 . 0.25 33. CO = 5mL, CH = 2 mL, N = 3 mL 3 4 . 10 mL 42
EXERCISE–04 [B] BRAIN STORMING SUBJECTIVE EXERCISE 1 . A crystalline hydrated salt on being rendered anhydrous, loses 45.6% of its weight. The percentage com- position of anhydrous salt is : Al = 10.5%, K = 15.1%, S = 24.8% and I = 49.6%. Find the empirical formula of the anhydrous and crystalline salt : 2 . How much quantity of zinc will have to be reacted with excess of dilute HCl solution to produce sufficient hydrogen gas for completely reacting with the oxygen obtained by decomposing 5.104 g of potassium chlorate? 3 . A 1.85 g sample of mixture of CuCl2 and CuBr2 was dissolved in water and mixed thoroughly with 1.8 g portion of AgCl. After reaction, the solid which now contain AgCl and AgBr was filtered, dried and weighed to be 2.052 g. What was the % by weight of CuBr2 in the mixture? 4 . 1.0 g of a sample containing NaCl, KCl and some inert impurity is dissolved in excess of water and treated with excess of AgNO3 solution. A 2.0 g precipitate to AgCl separate out. also sample is 23% by mass in sodium. Determine mass percentage of KCl in the sample : 5 . A mixture of CuSO4 . 5H2O and MgSO4 . 7H2O was heated until all the water was driven-off. If 5.0 g of mixture gave 3 g of anhydrous salts, what was the percentage by mass of CuSO4 . 5H2O in the original mixture : 6 . A compound containing Ca, C, N and S was subjected to quantitative analysis and formula mass deter- mination. A 0.25 g of this compound was mixed with Na2CO3 to convert all Ca into 0.16 g CaCO3. A 0.115 g sample of compound was carried through a series of reactions until all its S was changed into S O 2 and precipitated as 0.344 g of BaSO4 . A 0.712 g sample was processed to liberate all of its N as 4 NH3 and 0.155 g NH3 was obtained. The formula mass was found to be 156. Determine the empirical and molecular formula of the compound : 7 . A 0.2 g sample, which is mixture of NaCl, NaBr and NaI was dissolved in water and excess of AgNO 3 was added. The precipitate containing AgCl, AgBr and AgI was filtered, dried and weighed to be 0.412 g. The solid was placed in water and treated with excess of NaBr, which converted all AgCl into AgBr. The precipitate was then weighed to be 0.4881 g. It was then placed into water and treated with excess of NaI, which converted all AgBr into AgI. The precipitate was then weighed to be 0.5868 g. What was the percentage of NaCl, NaBr and NaI in the original mixture : 8 . 2.5 g of a sample containing Na2CO3 ; NaHCO3 and some non-volatile impurity on gentle heating loses 12% of its weight. Residue is dissolved in 100 mL water and its 10 mL portion required 15 mL 0.1 M aqueous solution of BaCl2 for complete precipitation of carbonates. Determine mass percentage of Na2CO3 in the original sample ? 9 . Based on the following information, determine value x and y : (CH 3 )x AlCl y xCH 4 (g ) yCl Al3 AgNO3 AgCl(s) 0.643 g 0.222 g 0.996 g 1 0 . A 5.0 g sample of felspar containing Na2O, K2O and some inert impurity is dissolved in dilute HCl solution and NaCl and KCl formed are separated by fractional crystallization. During crystallization some less soluble impurities also comes out. Mass of NaCl, KCl and impurity accompanying these salts was found to be 6.47 g. Solid crystal was then re-dissolved and required 300 mL of 0.3 M AgNO3 for complete precipitation of chlorides. The precipitate this, obtained was found to contain 4.23 % insoluble impurity. Determine mass percentage of Na O and K O in the original sample : 22 1 1 . Pb(NO3)2 and KI reacts in aqueous solution to form an yellow precipitate of PbI2. In one series of experi- ments, the masses of two reactants varied, but the total mass of the two was held constant at 5.0 g. What maximum mass of PbI2 can be produced in the above experiment : 1 2 . Uranium is isolated from its ore by dissolving it as UO (NO ) and separating it as solid UO (C O ). xH O. 2 32 2 24 2 A 1.0 g sample of ore on treatment with nitric acid yielded 1.48 g UO (NO ) which on further treatment 2 32 with 0.4 g Na C O yielded 1.23 g UO (C O ).xH O. Determine weight percentage of uranium in the 22 4 2 24 2 original sample and x :
1 3 . A mother cell disintegrate into sixty identical cells and each daughter cell further disintegrate into 24 smaller cells. The smallest cells are uniform cylindrical in shape with diameter of 120 Å and each cell is 6000 Å long. Determine molar mass of the mother cell if density of the smallest cell is 1.12 g/cm3 : 1 4 . A sample is a mixture of Mohr's salts and (NH4)2SO4. A 0.5 g sample on treatment with excess of BaCl2 solution gave 0.75 g BaSO4. Determine percentage composition of the salt mixture . What weight of Fe2O3 would be obtained if 0.2 g of the sample were ignited in air ? 1 5 . A chloride mixture is prepared by grinding together pure BaCl2.2H2O, KCl and NaCl. What is the smallest and largest volume of 0.15 M AgNO3 solution that may be used for complete precipitation of chloride from a 0.3 g sample of the mixture which may contain any one or all of the constituents ? 1 6 . One mole of a mixture of N , NO and N O has a mean molar mass of 55.4. On heating to a temperature 22 24 at which NO may be dissociated : NO 2NO2, the mean molar mass tends to the lower value 24 24 of 39.6. What is the mole ratio of N : NO : N O in the original mixture? 2 2 24 1 7 . 10 mL of gaseous organic compound contain C, H and O only was mixed with 100 mL of O and exploded 2 under identical conditions and then cooled. The volume left after cooling was 90 mL. On treatment with KOH a contraction of 20 mL was observed, if vapour density of compound is 23 derive molecular formula of the compound. 1 8 . Fluorocarbon polymers can be made by fluorinating polyethylene according to the reaction (CH ) + 4nCoF 2n 3 (CF ) + 2nHF + 4nCoF , where n is a large integer. The CoF can be regenerated by the reaction 2n 2 3 2 CoF + F 2CoF . If the HF formed in the first reaction cannot be reused, how many kg of fluorine 2 2 3 are consumed per kg of fluorocarbon produced, (CF ) ? If HF can be recovered and electrolyzed to hydrogen 2n and flurine, and if this fluorine is used for regenerating CoF , what is the net consumption of fluorine per 3 kg of fluorocarbon? 19. A + 2B AB 2 2 24 3 A+ 2B AB 2 2 34 2 Two substance A & B react in the above manner when A is limited it gives A B in excess gives A B . 22 2 24 34 A2B4 can be converted to A3B4 when reacted with A2. Using this information calculate the composition of the final mixture when the mentioned amount of A & B are taken :c (a) 4 moles A & 4 moles B 22 1 (b) moles A & 2 moles B 22 2 (c) 1.25 moles A & 2 moles B 22 2 0 . In a water treatment plant, Cl used for the treatment of water is produced from the following reaction 2 2KMnO + 16HCl 2KCl + 2MnCl + 8H O + 5Cl . If during each feed 1 L KMnO having 79% 4 22 2 4 (w/v) KMnO & 9 L HCl with d = 1.825 g/mL & 10% (w/w) HCl are entered & if that percent yield 4 is 80% then calculate : (a) amount of Cl produced. 2 (b) amount of water that can be treated by Cl if 1 litre consumes 28.4 g of Cl for treatment. 22 vol.of water treated (c) calculate efficiency of the process if = vol.of total feed 2 1 . A sea water sample has a density of 1.03 g/cm3 and 2.8% NaCl by mass. A saturated solution of NaCl in water is 5.45 M NaCl. How much water would have to be evaporated from 1.00 × 106 L of the sea water before NaCl would precipitate ? 2 2 . A sample of oleum is such that ratio of \"free SO \" by \"combined SO \" is equal to unity. Calculate its labelling 33 in terms of percentage oleum.
2 3 . One litre of milk weighs 1.035 kg. The butter fat is 4% (v/v) of milk has density of 875 kg/m3. Find the density of fat free skimed milk. 2 4 . A sample of fuming sulphuric acid containing H SO , SO and SO weighing 1.00 g is found to require 24 3 2 23.47 mL of 1.00 M alkali (NaOH) for neutralisation. A separate sample shows the presence of 1.50% SO . Find the percentage of \"free\" SO , H SO and \"combined\" SO in the sample. 2 3 24 3 2 5 . In one process for waterproofing, a fabric is exposed to (CH ) SiCl vapour. The vapour reacts with hydroxyl 32 2 groups on the surface of the fabric or with traces of water to form the waterproofing film [(CH ) SiO] , 32 n by the reaction ; n(CH ) SiCl + 2nOH 2nCl– + nH O + [(CH ) SiO] 32 2 2 32 n where n stands for a large integer. The waterproofing film is deposited on the fabric layer upon layer. Each layer is 6.0 Å thick [the thickness of the (CH3)2SiO group]. How much (CH3)2SiCl2 in needed to waterproof one side of a piece of fabric, 1.00 m by 3.00 m, with a film 300 layers thick ? The density of the film is 1.0 g/cm3. 2 6 . 20 mL of a mixture of methane and a gaseous compound of Acetylene series were mixed with 100 mL of oxygen and exploded. The volume of the products after cooling to original room temperature and pressure, was 80 mL and on treatment with potash solution a further contracting of 40 mL was observed. Calculate (a) the molecular formula of the hydrocarbon, (b) the percentage composition of the mixture. 2 7 . In a solution the concentration of CaCl is 5 M & that of MgCl is 5 m. The specific gravity of solution 22 is 1.05, calculate the concentration of Cl– in the solution in terms of Molarity. BRAIN STORMING SUBJECTIVE EXERCISE ANSWER KEY EXERCISE-4(B) 1. KAlS2O8 , KAlS2O8 . 12 H2O 2. 8.124 g Zn 3 . 34.18 4. 29.28 5. 74.4 6 . CaC2N2S2, CaC2N2S2 7. 50, 20.23, 29.77 8. 42.4 % Na2CO3 9 . 2, 1 10. 31.16, 37.34 11. 3.464 g 1 2 . 89.4, 3 13. 6.6 × 1010 g 14. 18.77 mg 1 5 . 16.38 mL, 34.18 L 16. 0.5 : 0.1 : 0.4 17. C2H6O 1 8 . 1.52 kg, 0.76 kg 19. (a) A3B4 = 2 & A2 = 1 ; A2B4 1 & B2 = 1 (c) A2B4 = 0.5 & A3B4 = 0.5 (b) = 2 20. (a) 10 mol, (b) L, (c) 2.5 21. 9.095 × 105 L 2 2 . 110.11 % 23. 1.041 g/mL 24. H SO = 35.38%, Free SO = 63.1%, combined SO = 28.89% 2 5 . 0.9413 gram 24 3 3 26. (b) 50 27. [Cl–] = 13.36 M
EXERCISE - 05 [A] JEE-[MAIN] : PREVIOUS YEAR QUESTIONS 1 . The weight of 2.01 × 1023 molecules of CO is [AIEEE-2002] (1) 9.3 g (2) 7.2 g (3) 1.2 g (4) 3 g 2 . In an organic compound of molar mass 108 g mol– 1 C, H and N atoms are present in 9 : 1 : 3.5 by weight. Molecular formula can be : [AIEEE-2002] (1) C6H8N2 (2) C7H10N (3) C5H6N3 (4) C4H18N3 3 . 6.02 × 1021 molecules of urea are present in 100 ml of its solution. The concentration of urea solution is - [AIEEE-2004] (1) 0.001 M (2) 0.01 M (3) 0.02 M (4) 0.1 M 4 . If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of the substance will :- [AIEEE-2005] (1) be a function of the molecular mass of the substance (2) remain unchanged (3) increase two fold (4) decrease twice 5 . How many moles of magnesium phosphate, Mg3(PO4)2 will contain 0.25 mole of oxygen atoms? [AIEEE-2006] (1) 3.125 × 10–2 (2) 1.25 × 10–2 (3) 2.5 × 10–2 (4) 0.02 6 . In the reaction [AIEEE-2007] 2Al(s) + 6HCl(aq) 2Al3+(aq) + 6Cl¯(aq) + 3H2(g). (1) 6L HCl(aq) is consumed for every 3L H2(g) produced (2) 33.6 L H2(g) is produced regardless of temperature and pressure for every mole Al that reacts (3) 67.2 L H2(g) at STP is produced for every mole Al that reacts (4) 11.2 L H2(g) at STP is produced for every mole HCl(aq) consumed 7 . Amount of oxalic acid present in a solution can be determined by its titration with KMnO solution in the 4 presence of H SO . The titration gives unsatisfactory result when carried out in the presence of HCl, because 24 HCl [AIEEE-2008] (1) gets oxidized by oxalic acid to chlorine (2) furnishes H+ ions in addition to those from oxalic acid (3) reduces permanganate to Mn2+ (4) oxidises oxalic acid to carbon dioxide and water 8 . If 10–4 dm3 of water is introduced into a 1.0 dm3 flask at 300 K, how many moles of water are in the vapour phase when equilibrium is established ? (Given : Vapour pressure of H2O at 300 K is 3170 Pa ; R = 8.314 JK–1 mol–1) :- [AIEEE-2010] (1) 1.27 × 10–3 mol (2) 5.56 × 10–3 mol (3) 1.53 × 10–2 mol (4) 4.46 × 10–2 mol 9 . A 5.2 molal aqueous solution of methyl alcohol, CH3OH, is supplied. What is the mole fraction of methyl alcohol in the solution ? [AIEEE-2011] (1) 0.086 (2) 0.050 (3) 0.100 (4) 0.190 1 0 . The mass of potassium dichromate crystals required to oxidise 750 cm3 of 0.6 M Mohr's salt solution is: (Given molar mass : potassium dichromate = 294, Mohr's salt = 392) :- [AIEEE-2011] (1) 0.49 g (2) 0.45 g (3) 22.05 g (4) 2.2 g 1 1 . The density of a solution prepared by dissolving 120 g of urea (mol. mass = 60 u) in 1000 g of water is 1.15 g/mL. The molarity of this solution is :- [AIEEE-2012] (1) 2.05 M (2) 0.50 M (3) 1.78 M (4) 1.02 M PREVIOUS YEARS QUESTIONS ANSWER KEY EXERCISE-5 [A] Que. 1 2 3 456 7 8 9 10 Ans. 1 1 4 114 3 113 Que. 11 Ans. 1
EXERCISE - 05 [B] JEE-[ADVANCED] : PREVIOUS YEAR QUESTIONS 1 . How many moles of e– weight one Kg : [JEE '2002 (Scr), 1] (A) 6.023 × 1023 (B) 1 1031 (C) 6.023 1054 (D) 1 108 9.108 9.108 9.108 6.023 2 . Calculate the molarity of pure water using its density to be 1000 kg m–3 : [JEE' 2003] 3 . One gm of charcoal adsorbs 100 mL 0.5 M CH COOH to form a monolayer, and there by the molarity 3 of CH COOH reduces to 0.49. Calculate the surface area of the charcoal adsorbed by each molecule of 3 acetic acid. Surface area of charcoal = 3.01 × 102m2/g : [JEE' 2003] 4 . Which has maximum number of atoms : [JEE 2003] (A) 24 g C(12) (B) 56 g Fe(56) (C) 27 g Al (27) (D) 108 g Ag(108) 5 . Calculate the amount of Calcium oxide required when it reacts with 852 g of P O . [JEE 2005] 4 10 6CaO + P4O10 2 Ca3 (PO4)2 6 . 20% surface sites have adsorbed N . On heating N gas evolved from sites and were collected at 0.001 22 atm and 298 K in a container of volume is 2.46 cm3. Density of surface sites is 6.023 × 1014/cm2 and surface area is 1000 cm2, find out the no. of surface sites occupied per molecule of N :[JEE 2005] 2 7 . Given that the abundances of isotoes 54Fe, 56Fe, 57Fe are 5%, 90% and 5% respectively, the atomic mass of Fe is : JEE 2009] (A) 55.85 u (B) 55.95 u (C) 55.75 u (D) 56.05 u PREVIOUS YEARS QUESTIONS ANSWER KEY EXERCISE -5 [B} 1. D 2 . 55.5 mol L–1 3. 5 × 10–19 m2 4. A 5 . 1008 g 6. 2 7. B
EXERCISE-01 CHECK YOUR GRASP SELECT THE CORRECT ALTERNATIVE (ONLY ONE CORRECT ANSWER) 1 . Consider the following reaction sequence CH2 = CH2 dil.KMnO4 A PCl5 B cold excess The products (A) and (B) are, respectively : (A) CH3CH2OH and CH3CH2Cl (B) CH3CHO and CH3CHCl2 (C) CH2OH CH2OH and CH2ClCH2Cl (D) CH2OHCH2OH and CH2OHCH2Cl 2 . Consider the following reaction sequence, CH3C CH HCl A aq.KOH B 2 mole Heat The products (A) and (B) are, respectively, (A) CH3CH2CHCl2 and CH3CH2CHO (B) CH3CCl2CH3 and CH3COCH3 (C) CH3CCl2CH3 and CH3C CH (D) CH3CHClCH2Cl and CH3CHOHCH2OH 3 . Consider the following chlorides : CH2Cl CH3 CH2Cl ; (B) (A) CH3O CH2Cl O2N CH2Cl ; (D) (C) The order of reactivity of A, B, C and D towards hydrolysis by SN1 mechanism is : (A) A < B < C < D (B) D < C < B < A (C) D < A < B < C (D) C < B < A < D 4 . In the following reaction sequence Ph – C CH aq.H2SO4 A 1.CH3MgI B Hg2 2.H2O the product (B) is : Ph CH3 (A) PhCOCH3 (B) PhCH2CHOHCH3 (C) C (D) PhCH2COCH3 CH3 OH 5 . Consider the following reaction. O16 CH3– C –O18 –C2H5 + H2O16 H Heat The products formed in the reaction are O16 O16 (A) CH3– C –O16H and C2H5O18H (B) CH3– C –O18H and C2H5O16H O16 O18 (C) CH3– C –O16H and C2H5O16H (D) CH3– C –O18H and C2H5O18H
6 . Consider the following reaction sequence, O 1.CH3MgI A POCl3 B 2.H2O P y rid in e ,0 C The product (B) is- CH3 CH3 CH2 CH3 (A) Cl (B) OPOCl2 (C) (D) 7 . Propene is allowed to react with m-chloroperoxobenzoic acid. The product (A) is then reduced with LiAlH4 in dry ether to give (B). CH3CH CH2 MCPBA A 1. LiAlH4 B 2. H3O The structure of the product (B) is: (A) CH3CHOHCH2OH (B) CH3CH2CH2OH (C) CH3CHOHCH3 (D) CH3–CH–CH2 O 8 . 2-Phenylethanol may be prepared by the reaction of phenylmagnesium bromide with : (A) HCHO (B) CH3CHO (C) CH3COCH3 (D) 9 . In the reaction O Cl CH2Br + CH3CHO + Mg dry ether A H3O B the product (B) is : (A) CH3CH CH2Br (B) Cl CH2CHCH3 OH OH (C) CH3–CH CH2CHCH3 (D) CH2=CH CH2Br OH OH 1 0 . The final product in the reaction is : Ph—OH + CCl4 KOH product (A) Salicyl aldehyde (B) Salicylic acid (C) Methyl salicylate (D) Benzyl chloride 1 1 . In the reaction of phenol with CHCl3 and aqueous NaOH at 70°C, the eletrophile attacking the ring is : (A) CHCl3 (C) CCl2 (D) COCl2 (B) C HCl2
OH 1 2 . CHCl3KOH Product : about above reaction the incorrect statement is (A) The name of reaction is Riemer teimann's reaction (B) The intermediate in the reaction is dichloro carbene (C) The final product is o-hydroxy benzaldehyde (D) the final product is benzyl chloride 1 3 . The final product (IV) in the sequence of reactions is : CH2 CH2 C H 3 C H O H PBr2 I Mg H2O | CH3 II O III IV Ether (A) CH3 CHOCH2CH2OH (B) CH3 CHCH2CH2Br CH3 CH3 (C) CH3 CH CH2CH2OH (D) CH3 CHOCH2CH3 CH3 CH3 1 4 . The reaction of 1 mol each of p-hydroxyacetophenone and methyl magnesium iodide will give : (A) CH4 + IMgO COCH3 (B) CH3O COCH3 OMgI OH (D) CH3O MgI (C) H3C C COCH3 CH3 O 1 5 . The product obtained in the reaction RCH CH2C OH ? is : OH O (A) RCH CH2 (B) R CH2 C O R O C= O CH HC O C CH2 O (C) RCH = CHCOOH (D) None of these
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- 324
- 325
