H.W Table-Some basic concept of Chemistry

ASSIGNMENT QUESTIONS 03-06-2021 LT-23 GP-1 ENGG CHEMISTRY: Some Basic Concepts of Chemistry 1. In an eperiment 2.4 g of iron oxide on reduction with hydrogen gave 1.68 g of iron. In another experiment, 2.9g of iron oxide gave 2.09 g of iron on reduction. Which law is illustrated from the data? A) Law of constant proportions B) Law of multiple proportions C) Law of reciprocal proportions D) Law of conservation of mass 1 2. An atom is 10 times heavier than 12th of mass of the C-12 carbon atom. The atomic mass is : A) 10 u B) 120 u C) 1.2 u D) 12 u 3. If the average atomic mass of an element having two isotopes is 71, the ratio of the natural abundance of the two isotopes of mass 70 and 74 will be A) 4:1 B) 3:1 C) 5:1 D) 6:1 4. The number of moles of electrons which weigh one kg is A) 6.02  1023 B) 1  1023 C) 6.02  1054 108 9.108 9.108 D) 9.108  6.02 5. If the vapour density of a gas with respect to methane is 2, molecular mass of the gas will be A) 4 u B) 16 u C) 8 u D) 32 u 6. A sample of PCl3 contains 1.4 moles of the substance. How many atoms are there in the sample? A) 4 B) 5.6 C) 8.431 x 1023 D) 3.372 x 1024 7. Which among the following statements is correct? A) 1 mol of electron has 1.6 × 10-19 C of charge B) 1 mol of electron has .16 × 10-19 C of charge C) 1 mol of electron weighs 0.54 Kg D) 1 mol of electron weighs 0.54 mg 8. In a compound C,H and N atoms are present in 9 : 1 : 3.5 by weight. Mol wt . of compound is 108, its mol.formula is A) C2H6N2 B) C3H4N C) C6H8N2 D) C9H12N3 9. When 22.4 litres of H2(g) is mixed with 11.2 litres of Cl2 (g), each at S.T.P. the moles of HCl (g) formed is equal to 1) 1 mol of HCl (g) 2) 2 mol of HCl (g) 3) 0.5 mol of HCl (g) 4) 1.5 mol of HCl (g) 10. Two elements X and Y combines to form two compounds XY2 and X3Y2 0.1 mol of XY2 weighs 10g and 0.05 mol of X3Y2 weighs 9g, the atomic weights of X and Y are respectively A) 40, 30 B) 60, 40 C) 20, 30 D) 30, 20 1

11. How many moles of lead (II) chloride will be formed from a reaction between 6.5g of PbO and 3.2g of HCl? [At. wt. Pb = 207g] A) 0.044 B) 0.333 C) 0.077 D) 0.029 12. Caffein has molecular weight of 194. It contain 28.9% by mass of nitrogen. Number of atoms of nitrogen in one molecule of it is A) 2 B) 3 C) 4 D) 5 13. The volume at STP of pure O2 necessary for the complete combustion of 12 g of magnesium of atomic weight 24 is: A) 22.4 dm3 B) 11.2 dm3 C) 5.6 dm3 D) 12 dm3 14. An unknown element forms an oxide. What will be the equivalent weight of the element if the oxygen content is 20% by weight? A) 8 B) 16 C) 24 D) 32 15. A 100% pure sample of a divalent metal carbonate weighing 2g on complete thermal decomposition re- leases 448 mL of carbondioxide at STP. The equivalent mass of the metal is: A) 40 B) 20 C) 28 D) 12 16. The number of oxalic acid molecules in 100 mL of 0.02 N oxalic acid is A) 12.05 × 1023 B) 12.05 × 1020 C) 12.05 × 1021 D) 6.023 × 1020 17. An aqueous solution of 6.3 g of oxalic acid dihydrate is made up of 250 mL. The volume of 0.1 N NaOH required to completely neutralize 10 mL of this solution is A) 20 mL B) 10 mL C) 5 mL D) 40 mL 18. To 100 ml CaCl2 solution containing 6.66g CaCl2, 100 ml of 0.5M Na3PO4 solution is added. The mass of Ca3(PO4)2 precipitated would be ? (Ca = 40u, P = 31u, O = 16u) A) 4.2 g B) 5.0 g C) 6.2 g D) 7.6 g 19. 10 mL of 2(M) NaOH solution is added to 200 mL of 0.5 (M) of NaOH solution. What is the final concentration of the resultant solution? A) 0.57 (M) B) 5.7 (M) C) 11.4 (M) D) 1.14 (M) 20. If 1021 molecules are removed from 200 mg of CO2 , the number of moles of CO2 left is A) 2.88103 B) 28.8103 C) 0.288103 D) 1.66 102 21. A gaseous hydrocarbon gives upon combustion 0.72 g of water and 3.08 g of CO2. The empirical formula of the hydrocarbon is: A) C2H4 B) C3H4 C) C6H5 D) C7H8 22. Chlorine gas is prepared by reaction of H2SO4 with MnO2 and NaCl. What volume of Cl2 will be produced at STP if 50 g of NaCl react with excess amount of MnO2 and H2SO4? A) 1.915L B) 22.4 L C) 11.2 L D) 9.57 L 23. The molecular formula of the oxide of iron in which mass percentage of iron is 70 (Fe = 56u) A) FeO B) Fe2O3 C) Fe3O3 D) Fe3O4 2

24. In an experiment, 4g of M2Ox(oxide) was reduced to 2.8g of the metal. If the atomic mass of metal is 56, the number of oxygen atoms in the oxide is A) 1 B) 2 C) 3 D) 4 25. 4.4 g of CO2 and 2.24 L H2 and STP are mixed in a container. The total number of molecules present in the container will be A) 6.022 × 1023 B) 1.2044 × 1023 C) 12.044 × 1023 D) 6.022 × 1024 26. In an experiment, 4g of M2Ox(oxide) was reduced to 2.8g of the metal. If the atomic mass of metal is 56, the number of oxygen atoms in the oxide is A) 1 B) 2 C) 3 D) 4 27. 1.0 g of magnesium is burnt with 0.56 g O2 in a closed vessel. Which reactant is left in excess and how much ? (At.wt.Mg = 24, O = 16) A) Mg, 0.16 g B) O2, 0.16 g C) Mg, 0.44 g D) O2, 0.28 g 28. The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is : A) 10 B) 20 C) 30 D) 40 29. The molality of X% H2SO4 solution is equal to 9. The weight of the solvent present in the solution is 910 g. The value of ‘X’ is. A) 90 B) 80.3 C) 40.13 D) 9 30. Molarity of 560 g pure H2O at 4oC is A) 40 B) 4 C) 55.5 D) 44.6 31. The mass of 60% HCI required for the netralisation of 10L of 0.1 MKOH is A) 60.8 g B) 21.9 g C) 100 g D) 219 g 32. The number of moles of H2 in 0.224 litre of hydrogen gas at STP (273 K, 1 atm) (assumming ideal gas behaviour) is A) 1 B) 0.1 C) 0.01 D) 0.001 33. 40% W/V NaCl solution (specific gravity = 1.12) is equivalent to A) 3.57 × 105 ppm B) 3.57 × 106 ppm C) 1.106 ppm D) 4 × 105 ppm 34. The volume of water that must be added to a mixture of 250ml of 0.6M HCl and 750ml of 0.2M HCl to obtain 0.25M solution of HCl is A) 750ml B) 100ml C) 200ml D) 250ml More than one correct 35. Choose the correct statements: A) The number of atoms in 1 g of helium is 1.506 × 1022 B) The mass of 1 molecule of CO is 4.65 × 10-23g C) The volume at STP occupied by 240g of SO2 is 22.4 litre D) The volume at STP occupied by 240g of SO2 is 84 litre 3

36. In which of the following pairs do 1 g of each have an equal number of molecules? A) N2O and CO B) N2 and C3O2 C) N2 and CO D) N2O and CO2 37. One litre of oxygen at STP is made to react with three litres of carbon monoxide at STP. Then A) Volume of CO used = 2 L B) Volume of CO left = 1L C) Volume of O2 used = 0.5 L D) Oxygen is the limiting agent 38. A compound contains 4.07 % hydrogen, 24.27 % carbon and 71.65 % chlorine. Its molar mass is 98.96 g. Then A) Vapour density of the compound = 49.48 B) Empirical formula of the compound = CH2Cl C) Empirical mass of the compound = 49.5 D) Molecular formula of the compound = C2H4Cl2 39. Which statements are wrong regarding concentration methods used in solution ? A) Molarity and normality are temperature dependent B) Molarity of water in its 1 L is 27.25 M C) 1 M HCl solution has a normality of 1 N D) ppm is also known as  gL-1 40. 20 g of CaCO3 is reacted with 20 g of HCl, then A) HCl is limiting reagent B) CaCO3 is limiting reagent C) Amount of CO2 produced is 8.8 g D) Amount of CO2 produced is 88 g 41. Which of the following statement is/are correct? A mixture containing 64 g H2 and 64 g O2 is ignited so that water is formed as follows: 2H2  O2 2H2O A) H2 is the limiting reagent B) O2 is the limiting reagent C) The reaction mixture contain 72 g of H2O and 56 g of unreacted H2 D) The reaction mixture contains 56 g of H2O and 72 g of unreacted H2 Integer / Numerical type 42. For a reaction A  2B  C , the amount of C formed by starting the reaction with 5 moles of A and 8 moles of B is 43. In 1200 g solution, 12 g urea (NH2CONH2) is present if density of the solution is 1.2 g/ml then molarity. If the solution is xM find 10 x ? 44. Mass of 22.4 L of a gas at STP is 20 g. Then the molar mass of the gas is 45. 6 g acetic acid (CH3COOH) dissolved in 100 g benzene (C6H6).Then molality of the solution is 4

46. 0.3 g of an acid is neutralised by 40 cm3 of 0.125 N NaOH. Equivalent mass of the acid is 47. The measured density at NTP of He is 0.1784 g/L. What is the mass of one mole of He? 48. Column-I Column-II A) 2 mol octane required p)1100 g O2 for completely combustion q) 11.2 L at 0oC and 1 atom B) 300 g carbon combines with 800 g of oxygen to produce CO2 r) 25 mol C) 1 g-atom of Nitrogen D) 124 g of NO3 ion s) 48. 16 × 1023 atoms A) A  p, r, t; B  p, r, t; C  q ; D  s t) 800 g C) A  r, t; B  p, r; C  q ; D  s, t B) A  r, t; B  p, r; C  q ; D  s 49. Column-I D) A  r, t; B  p, r; C  p, q ; D  s Column-II a) N2 (3.5 g) +H2 (1.0g)  NH3 p) First reactant is the limiting reagent b) H2 (1.0 g)  O2 (4.0 g)  H2O q) Second reactant is the limiting reagent c) S(4.0 g)  O2 (6.0 g)  SO3 r) Stoichiometric amounts of reactants d) Fe (11.2 g) + O2 (3.2 g)  Fe2O3 s) Mass of reactants > mass of product formed A) a  p; b  q, s; c  r; d  p, q, s C) a  p, s; b  q, s; c  r; d  q, s B) a  p, q, s; b  q, r, s; c  r; d  q, s 50. Column I D) a  q, s; b  q, s; c  r; d  q, s a) 1g ion of Na+ b) 23 g of Na Column II c) 1 g ion of Mg2+ p) 6.02 × 1024 electrons d) 24 g of Mg q) 7.224 × 1024 neutrons A) a - p,q ; b - q; c - p, q, r, s; d - q, s r) 6.02 × 1023 × 2 × 1.6 × 10-19 columb charge C) a - p,q ; b - p, q; c - p, q, r, s; d - q, s s) 7.224 × 1024 proton B) a - p,q, r ; b - q; c - p, q, r, s; d - q, s D) a - p,q ; b - q; c - p, q; d - q, s 5

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1. A ANSWER KEY 2. A 3. B 26. C 4. D 27. B 5. D 28. C 6. D 29. D 7. D 30. C 8. C 31. A 9. A 32. C 10. A 33. A 11. D 34. C 12. C 35. B, D 13. C 36. C, D 14. D 37. A, B, D 15. B 38. A, B, C, D 16. D 39. B, D 17. D 40. B, C 18. C 41. B, C 19. A 42. 4 20. A 43. 2 21. D 44. 20 22. D 45. 1 23. B 46. 60 24. C 47. 4 25. B 48. B 49. C 50. A 7