Laws of Chemical Combination

PRARAMBH EXERCISE-1 (TOPICWISE) LAW OF CHEMICAL COMBINATIONS 1. In Haber's process, the volume at S.T.P of ammonia relative to the total volume of reactants at STP is: (1) One fourth (2) One half (3) Same (4) Three fourth 2. 6 g of carbon combines with 32 g of sulphur to form CS2, 12 g of C also combine with 32 g oxygen to form CO2. 10 g of sulphur combines with 10 g of oxygen to form Sulphur dioxide. Which law is illustrated by this? (1) Law of multiple proportions (2) Law of constant composition (3) Law of reciprocal proportions (4) Gay Lussac’s law 3. Which of the following data illustrates the law of conservation of mass? (1) 56 g of C reacts with 32 g of Oxygen to produce 44 g of CO2 (2) 1.70 g of AgNO3 reacts with 100 ml of 0.1M HCl to produce 1.435 g of AgCl and 0.63 g of HNO3 (3) 12 g of C is heated in vacuum and on cooling, there is no change in mass (4) 36 g of S reacts with 16 g of O2 to produce 48 g of SO2 4. One part of an element A combines with two parts of another element B, 6 parts of element C combines with 4 parts of (B) If A and C combine together the ratio of their weights, will be governed by: (1) law of definite proportion (2) law of multiple proportion (3) law of reciprocal proportion (4) law of conservation of mass 5. The law of conservation of mass holds good for all of the following except. (1) All chemical reactions (2) Nuclear reaction (3) Endothermic reactions (4) Exothermic reactions 6. The % of copper and oxygen in samples of CuO obtained by different methods were found to be same. This proves the law of: (1) Constant Proportion (2) Reciprocal Proportion (3) Multiple Proportion (4) Conservation of mass. 7. Two elements X and Y combine in gaseous state to form XY in the ratio 1 : 35.5 by mass. The mass of Y that will be required to react with 2 g of X is: (1) 7.1 g (2) 3.55 g (3) 71 g (4) 35.5 g 8. 4.4 g of an oxide of nitrogen gives 2.24 L of nitrogen and 60 g of another oxide of nitrogen gives 22.4 L of nitrogen at S.T.P. The data illustrates: (1) Law of conservation of mass (2) Law of constant proportions (3) Law of multiple proportions (4) Law of reciprocal proportions 9. “The total mass of reactants is always equal to the total mass of products in a chemical reaction”. This statement is konwn as: (1) Law of conservation of mass (2) Law of definite proportions (3) Law of equivalent weights (4) Law of combining masses 10. The law of multiple proportions is illustrated by the two compounds: (1) Sodium chloride and sodium bromide (2) Ordinary water and heavy water (3) Caustic soda and caustic potash (4) Sulphur dioxide and sulphur trioxide 11. If law of conservation of mass was to hold true, then 20.8 g of BaCl2 on reaction with 9.8 g of H2SO4 will produce 7.3 g of HCl and BaSO4 equal to: (1) 11.65 g (2) 23.3 g (3) 25.5 g (4) 30.6 g 12. One of the following combinations which illustrates the law of reciprocal proportions is: (1) N2O3, N2O4, N2O5 (2) NaCl, NaBr, NaI (3) CS2, CO2, SO2 (4) PH3, P2O3, P2O5 ATOMIC AND MOLECULAR MASSES 13. Insulin contains 3.4% sulphur by mass. What will be the minimum molecular weight of insulin? (1) 94.117 u (2) 1884 u (3) 941 u (4) 976 u 14. Boron has two isotopes B 10 and B 11 whose relative abundances are 20% and 80% respectively. Atomic weight of Boron is: (1) 10 (2) 11 (3) 10.5 (4) 10.8 15. Avogadro’s number is the number of molecules present in: (1) 1 g of molecule (2) 1 atom of molecule (3) gram molecular mass (4) 1 litre of molecule 16. One amu is equal to: (1) 1.66 × 10–8 g (3) 1.66 × 10–16 g (2) 1.66 × 10–4 g (4) 1.66 × 10–24 g 17. The number of molecules present in one milli litre of a gas at STP is known as: (1) Avogadro number (2) Boltzman number (3) Loschmidt number (4) Universal gas constant MOLE CONCEPT AND MOLAR MASSES 18. 1 g-atom of nitrogen represents: (1) 6.02 × 1023 N2 molecules (2) 22.4 L of N2 at S.T.P (3) 11.2 L of N2 at S.T.P (4) 28 g of nitrogen 19. Which is correct for 10 g of CaCO3? (1) It contains 1 g atom of carbon (2) It contains 0.3 g atoms of oxygen (3) It contains 12 g of calcium (4) It refers to 0.1 g equivalent of CaCO3 20. The number of oxygen atoms present in 14.6 g of magnesium bicarbonate is: (1) 6 NA (2) 0.6 NA (3) NA (4) N A 2 21. Which of the following has the highest mass? (1) 20 g of sulphur (2) 4 mol of carbon dioxide (3) 12 × 1024 atoms of hydrogen (4) 11.2 L of helium at N.T.P. 22. If isotopic distribution of C 12 and C 14 is 98% and 2% respectively, then the number of C14 atoms in 12 g of carbon is: (1) 1.2 × 1022 (2) 3.01 × 1022 (3) 5.88 × 1023 (4) 6.02 × 1023 23. 5.6 L of a gas at S.T.P. weights equal to 8 g. The vapour density of gas is: (1) 32 (2) 16 (3) 8 (4) 40 24. One atom of an element weighs 1.8 × 10–22 g, its atomic mass is: (1) 29.9 g (2) 18 g (3) 108.36 g (4) 154 g 25. If H2SO4 ionises as H2SO4 + 2H2O →2H3O+ + SO42–. Then total number of ions produced by 0.1 mol H2SO4 will be: (1) 9.03 × 1021 (2) 3.01 × 1022 22 (3) 6.02 × 10 (4) 1.8 × 1023 28. A person adds 1.71 gram of sugar (C12H22O11) in order to sweeten his tea. The number of carbon atoms added are: (mol mass of sugar = 342) (1) 3.6 × 1022 (2) 7.2 × 1021 (3) 0.05 (4) 6.6 × 1022 29. The number of atoms present in 0.1 mole of P4 (at. mass = 31) are: (1) 2.4 × 1024 atoms (2) Same as in 0.05 mol of S8 (3) 6.02 × 1022 atoms (4) Same as in 3.1g of phosphorus 30. Which one contains maximum number of molecules? (1) 2.5 g molecule of N2 (2) 4 g atom of nitrogen (3) 3.01 × 1024 atoms of H2 (4) 82 g of dinitrogen 31. Out of 1.0 g dioxygen, 1.0 g (atomic) oxygen and 1.0 g ozone, the maximum number of oxygen atoms are contained in: (1) 1.0 g of atomic oxygen (2) 1.0 g of ozone (3) 1.0 g of oxygen gas (4) All contain same number of atoms 32. The maximum volume at S.T.P. is occupied by: (1) 12.8 g of SO2 (2) 6.02 × 1022 molecules of CH4 (3) 0.5 mol of NO2 (4) 1g molecule of CO2 33. If NA is Avogadro’s number, then the number of oxygen atoms in one g-equivalent of oxygen is [O2 + 4e → 2O2–]: (1) NA (2) NA/2 (3) NA/4 (4) 2NA 34. If 224 ml. of a triatomic gas has a mass of 1g at 273 K and 1 atm pressure, then the mass of one atom is: (1) 8.30 × 10–23 g (2) 6.24 × 10–23 –23 (3) 2.08 × 10 g (4) 5.54 × 10–23 g 35. The rest mass of an electron is 9.11 × 10–31 kg. Molar mass of the electron is: (1) 1.5 × 10–31 kg mol–1 (2) 9.11 × 10–31 kg mol–1 (3) 5.5 × 10–7 kg mol–1 (4) 6.02 × 1023 kg mol–1 36. A sample of ammonium phosphate, (NH4)3 PO4, contains 3.18 moles of hydrogen atoms. The number of moles of oxygen atoms in the sample is: (1) 0.265 (2) 0.795 (3) 1.06 (4) 3.18 (3) 0.16 mol of CO32- ions (4) 7.525 × 1022 Br atom 37. What is the total number of atoms present in 25.0 mg of camphor, C10H16O? (1) 9.89 × 1019 (2) 6.02 × 1020 20 (3) 9.89 × 10 (4) 2.67 × 1021 27. x L of N2 at S.T.P. contains 3 × 1022 molecules. The number of molecules in x/2 L of ozone at S.T.P. will be: (1) 3 × 1022 (2) 1.5 × 1022 (3) 1.5 × 1021 (4) 1.5 × 1011 38. Which of the following samples contains the largest number of atoms? (1) 1 g of CO2 (2) 1 g of C8H18 (3) 1 g of C2H6 (g) (4) 1 g of LiF (s) 26. Which of the following will not have a mass of 10 g? (1) 0.1 mol CaCO3. (2) 1.51 × 1023 Ca2+ ions 39. 4.0 g of caustic soda (NaOH) (mol mass 40) contains same number of sodium ions as are present in: (1) 10.6 g of Na2CO3 (mol. mass 106) (2) 58.5 g of NaCl (Formula mass 58.5) (3) 100 ml of 0.5 M Na2SO4 (Formula mass 142) (4) 1 mol of NaNO3 (mol. mass 85) 40. Total number of atoms present in 64 gm of SO2 is: (1) 2 × 6.02 × 1023 (2) 6.02 × 1023 23 (3) 4 × 6.02 × 10 (4) 3 × 6.02 × 1023 41. The total number of protons, electrons and neutrons in 12 gm of 6C12 is: (1) 1.084 × 1025 (2) 6.022 × 1023 22 (3) 6.022 × 10 (4) 18 42. Number of Ca+2 and Cl– ions in 111 g of anhydrous CaCl2 respectively are: (1) NA, 2NA (2) 2NA, NA (3) NA, NA (4) None of these 43. The maximum volume at N.T.P. is occupied by: (1) 12.8 gm of SO2 (2) 6.02 × 1022 molecules of CH4 (3) 0.5 mol of NO2 (4) 1 gm-molecule of CO2 44. Number of moles of water in 488 g of BaCl2.2H2O are (Ba = 137): (1) 2 moles (2) 4 moles (3) 3 moles (4) 5 moles 45. 4.4 g of CO2 and 2.24 litre of H2 at STP are mixed in a container. The total number of molecules present in the container will be: (1) 6.022 × 1023 (2) 1.2044 × 1023 (3) 2 moles (4) 6.023 × 1024 46. The total number of electrons in 1.6 g of CH4 to that in 1.8 g of H2O is: (1) Same (2) One half (3) One fourth (4) Double 47. One mole of nitrogen gas has volume equal to: (1) 1 litre of nitrogen at S.T.P. (2) 32 litre of nitrogen at S.T.P. (3) 22.4 litre of nitrogen at S.T.P. (4) 11.2 litre of nitrogen at S.T.P. 48. 23g of sodium will react with ethyl alcohol to give: (1) 1 mole of H2 (2) 1/2 mole of H2 (3) 1 mole of O (4) 1 mole of NaOH 49. If we assume 1/24 th part of mass of carbon instead of 1/12 th part of it as 1 amu., mass of 1 mole of a substance will: (1) Remain unchanged (2) get doubled (3) Get halved (4) can’t be predicted PERCENTAGE COMPOSITION AND EMPIRICAL & MOLECULAR FORMULA 50. The percentage of C, H and N in an organic compound are 40%, 13.3% and 46.7% respectively then empirical formula is: (1) C3H13N3 (2) CH2N (3) CH4N (4) CH6N 51. B1 g of an element gives B2 g of its chloride, the equivalent mass of the element is: (1) B1 ´35.5 B2 - B1 (3) B2 - B1 ´35.5 B1 (2) B2 ´35.5 B2 - B1 (4) B2 - B1 ´35.5 B2 52. 60 g of a compound on analysis gave 24 g C, 4 g H and 32 g O. The empirical formula of the compound is: (1) C2H4O2 (2) C2H2O2 (3) CH2O2 (4) CH2O 53. A compound made of two elements A and B are found to contain 25% A (at mass 12.5) and 75% B (at mass 37.5). The simplest formula of the compound is: (1) AB (2) AB2 (3) AB3 (4) A3B 54. 400 mg of capsule contains 100 mg of ferrous fumarate. The percentage of Fe present in the capsule is approximately: (formula of ferrous fumarate is (CHCOO)2 Fe). (1) 8.2% (2) 25% (3) 16% (4) Unpredictable 55. Simplest formula of compound containing 50% of element X (at mass 10) and 50% of element Y (at mass 20) is: (1) XY (2) X2Y (3) XY2 (4) X2Y3 56. A compound having the empirical formula (C3H4O) has a molecular mass of 170 ± 5. The molecular formula of it’s compound is: (1) C3H4O (2) C6H8O2 (3) C6H12O3 (4) C9H12O3 57. Two oxides of a metal contains 50% and 40% metal (M) respectively. If the formula of first oxide is MO2, the formula of second oxide will be: (1) MO2 (2) MO3 (3) M2O (4) M2O5 58. The vapour density of gas A is four times that of B. If molecular mass of B is M, then molecular mass of A is: (3) M (4) 2 M 4 59. A metal nitride M3N2 contains 28% of nitrogen. The atomic mass of metal M is: (1) M (2) 4 M (1) 24 (2) 54 (3) 9 (4) 87.62 60. A container of volume V, contains 0.28 g of N2 gas. If same volume of an unknown gas under similar conditions of temperature and pressure weights 0.44 g, the molecular mass of gas is: (1) 22 (2) 44 (3) 66 (4) 88 72. The molarity of pure water is: (1) 100 M (2) 55.6M (3) 50 M 61. A gaseous hydrocarbon on complete combustion gives 3.38 g of CO2 and 0.690 g of H2O and no other products. The empirical formula of hydrocarbon is: (1) CH (2) CH2 (3) CH3 (4) The data is not complete 74. If potassium chlorate is 80% pure then 48 g of oxygen would be produced from: (1) 153.12 g of KClO3 (2) 120 g of KClO3 (3) 20 g of KClO3 (4) 90 g of KClO3 62. The percentage of Carbon in CO2 is: (1) 27.27% (2) 29.27% (3) 30.27% (4) 26.97% 63. The haemoglobin from red blood corpuscles of most mammals contain approximately 0.33% of iron by mass. The molecular mass of haemoglobin is 67200. The number of iron atoms in each molecule of haemoglobin is: (1) 3 (2) 4 (3) 2 (4) 6 64. On analysis a certain compound was found to contain iodine and oxygen in the ratio of 254 g of iodine (at mass 127) and 80 g oxygen (at mass 16). What is the formula of compound? (1) IO (2) I2O (3) I5O3 (4) I2O5 65. 0.5 mol of potassium ferrocyanide contains carbon equal to: (Formula of potassium ferrocyanide is K4[Fe(CN)6]. (1) 1.5 mol (2) 36 g (3) 18 g (4) 3.6 g STOICHIOMETRY & CONCENTRATION TERMS (4) 18 M 73. The mass of 70% H2SO4 by mass is required for neutralisation of 1 mole of NaOH is: (1) 65 (2) 98 (3) 70 (4) 54 75. Density of a solution containing x% by mass of H2SO4 is y. The normality is: xy × 10 xy × 10 ×2 (1) (2) 98 y 98 x × 10 xy × 10 ×2 (4) 98 y 98 76. Number of gram equivalents of solute in 100 ml of 5 N HCl solution is: (1) 50 (2) 500 (3) 5 (4) 0.5 (3) 77. If 1.26 grams of oxalic acid is dissolved in 250 ml of solution then its normality is: (1) 0.05 (2) 0.04 (3) 0.02 (4) 0.08 78. 100 ml of ethylalcohol is made upto a litre with distilled water. If the density of C2H5OH is 0.46 gm/ml. Then its molality is: (1) 0.55 m (2) 1.11m (3) 2.22 m (4) 3.33m 66. ‘X’ litres of carbon monoxide is present at STP. It is completely oxidized to CO2. The volume of CO2 formed is 11.207 litres at STP. What is the value of ‘X’ in litres? (1) 22.414 (2) 11.207 (3) 5.6035 (4) 44.828 79. When 100 ml of M/10 H2SO4 is mixed with 500 ml of M/10 NaOH then nature of resulting solution and normality of excess of reactant left is: (1) Acidic, N/5 (2) Basic, N/5 (3) Basic, N/20 (4) Acidic, N/10 67. The volume of phosgene formed at STP when 11.2 lit of chlorine reacts with carbon monoxide is: (1) 11.2 lit (2) 22.4 lit (3) 5.6 lit (4) 44.8 lit 80. If 20 g of CaCO3 is treated with 100 mL 20% HCl solution. The amount of CO2 produced is: (1) 22.4l g (2) 8.8 g (3) 2.2 g (4) 8 l 68. What mass of CaCl2 in grams would be enough to produce 14.35 gm of AgCl? 81. The mass of CaCO3 required to react with 25 mL of 0.75 molar HCl is: (1) 0.94 g (2) 0.68 g (3) 0.76 g (4) 0.52 g CaCl2 + 2AgNO3 → Ca (NO3)2 + 2 AgCl (1) 5.55 g (2) 8.29 g (3) 16.59 g (4) 10 g 69. Benzene burns in oxygen according to the equation 2C6H6(I) +15O2(g) → 12CO2(g) + 6H2O(l). How many litres of oxygen are required at STP for the complete combustion of 39 g of liquid benzene? (1) 74L (2) 84L (3) 22.4L (4) 11.2L 70. H2O2 is sold as a solution of approximately 5.0 g H2O2 per 100 mL of the solution. The molarity of this solution is approximately: (1) 0.15 M (2) 1.5 M (3) 3.0 M (4) 3.4 M 71. The amount of oxalic acid (eq.wt.63) required to prepare 500 ml of its 0.10 N solution is: (1) 0.315 g (2) 3.150 g (3) 6.300 g (4) 63.00 g 82. 2 moles of H2S and 11.2 L of SO2 at S.T.P. reacts to form x moles of sulphur. The value of x is: (1) 1.5 (2) 3.5 (3) 7.8 (4) 12.7 83. The volume of CO 2 obtained at STP by the complete decomposition of 9.85 g Na2CO3 is: (1) 2.24L (2) Zero (3) 0.85L (4) 0.56L 84. The specific gravity of 98% H2SO4 is 1.8 g/cc. 50 ml of this solution is mixed with 1750 ml of pure water. Molarity of resulting solution is: (1) 0.2 M (2) 0.5 M (3) 0.1 M (4) 1 M 85. What is the mole fraction of solvent in aqueous solution of NaOH having molality of 3 is: (1) 0.3 (2) 0.95 (3) 0.7 (4) 0.05