Some Basic Concepts of Chemistry PYQs Set 8 (PDF)

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Some Basic Concepts of Chemistry · Set 8 (Q211-240)
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211. $The statement related to law of definite proportions is$ (1) $The ratio of oxygen in H_{2} O and H_{2} O_{2} with respect to fixed mass of Hydrogen atom is a whole number$ (2) $% of oxygen in H_{2} O is constant irrespective of the source$ (3) $Equal volume of all gases at the same temperature and pressure should contain equal number of molecules$ (4) $Matter can neither be created nor destroyed.$ 212. $The decomposition of a certain mass of CaCO_{3} gave 11.2 dm^{3} of CO_{2} gas at STP. The mass of KOH required to completely neutralise the gas is$ (1) $56 g$ (2) $28 g$ (3) $42 g$ (4) $20 g$ 213. $0.12 g of an organic compound ' X' containing phosphorus on reacting with magnesia mixturc gave 0.22 g of magnesium pyrophosphate (Mg_{2} P_{2} O_{7}) . The percentage of phosphorus in the compound ' X' is \dots \dots \dots$ (1) $45.30 %$ (2) $28.70 %$ (3) $64.25 %$ (4) $51.20 %$ 214. $An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be$ (1) $CHO$ (2) $C H_{2} O$ (3) $C H_{3} O$ (4) $C H_{4} O$ 215. $To an aqueous solution containing ions such as A l^{3 +}, Z n^{2 +}, C a^{2 +}, F e^{3 +}, N i^{2 +}, B a^{2 +} and C u^{2 +} was added conc. HCl, followed by H_{2} S . The total number of cations precipitated during this reaction is/are:$ (1) $1$ (2) $3$ (3) $4$ (4) $2$ 216. $If 50 % of 1 M Na_{2} SO_{4} is dissociated in aqueous solution of density 1.2 g mL^{- 1}, what is the molality of Na^{+} ion in the solution?$ (1) $0.95$ (2) $1.89$ (3) $1.00$ (4) $2.00$ 217. $A carbon compound contains 12.8 % of carbon, 2.1 % of hydrogen and 85.1 % of bromine. The molecular weight of the compound is 187.9. Calculate the molecular formula of the compound. (Atomic weight: H = 1.008, C = 12.0, Br = 79.9)$ (1) $CH_{3} Br$ (2) $CH_{2} Br_{2} I$ (3) $C_{2} H_{4} Br_{2}$ (4) $C_{2} H_{3} Br_{3}$ 218. $Chlorine is allowed to react with excess of ammonia. In this, 1 mole of chlorine can oxidise ' Z' moles of NH_{3}, ' Z' is$ (1) $\frac{3}{8}$ (2) $\frac{8}{3}$ (3) $\frac{2}{3}$ (4) $\frac{3}{2}$ 219. $On combustion 0.210 g of an organic compound containing C, H and O gave 0.127 g H_{2} O and 0.307 g CO_{2} . The percentages of hydrogen and oxygen in the given organic compound respectively are:$ (1) $7.55, 43.85$ (2) $6.72, 53.41$ (3) $6.72, 39.87$ (4) $53.41, 39.6$ 220. $14.0 g of calcium metal is allowed to react with excess HCl at 1.0 atm pressure and 273 K. Which of the following statements is incorrect? [Given : Molar mass in gmol^{- 1} of Ca - 40, Cl - 35.5, H - 1]$ (1) $0.35 mol of H_{2} gas is evolved.$ (2) $7.84 L^{2} of H_{2} gas is evolved.$ (3) $The limiting reagent is calcium metal.$ (4) $33.3 g of CaCl_{2} is produced.$ 221. $A solution is prepared by adding 2 g of "X" to 1 mole of water. Mass percent of "X" in solution is$ (1) $5%$ (2) $20%$ (3) $2%$ (4) $10%$ 222. $In which case is number of molecules of water maximum?$ (1) $18 m L of water$ (2) $0.18 g of water$ (3) $0.00224 L of water vapours at 1 atm and 273 K$ (4) $1 0^{- 3} mol of water$ 223. $The sum of three values 12.0, 19.034 and 2.0143 is equal to X . The number of significant figures in X is$ (1) $2$ (2) $5$ (3) $4$ (4) $3$ 224. $Given the numbers: 161 cm, 0.161 cm, 0.0161 cm. The number of significant figures for the three numbers is$ (1) $3, 3 and 4 respectively$ (2) $3, 4 and 4 respectively$ (3) $3, 4 and 5 respectively$ (4) $3, 3 and 3 respectively.$ 225. $How much mass of sodium acetate is required to make 250 mL of 0.575 molar aqueous solution?$ (1) $11.79 g$ (2) $15.38 g$ (3) $10.81 g$ (4) $25.35 g$ 226. $Observe the following reaction I_{2} + 10 HNO_{3} \to 2 HIO_{3} + 10 NO_{2} + 4 H_{2} O The equivalent wt. of HNO_{3} is (molar mass of HNO_{3} = M)$ (1) $M$ (2) $\frac{M}{4}$ (3) $\frac{M}{2}$ (4) $\frac{M}{5}$ 227. $The dimensions of pressure are the same as that of$ (1) $force per unit volume$ (2) $energy per unit volume$ (3) $force$ (4) $energy.$ 228. $The volume of 0.1 M oxalic acid that can be completely oxidized by 20 mL of 0.025 M KMnO_{4} solution is$ (1) $125 mL$ (2) $25 mL$ (3) $12.5 mL$ (4) $37.5 mL$ 229. $Which of the following reactions is an example of a redox reaction?$ (1) $XeF2 + PF5 \to [XeF]+ P F_{6}^{-}$ (2) $XeF6 + H2O \to XeOF4 + 2HF$ (3) $XeF6 + 2H2O \to XeO2F2 + 4HF$ (4) $XeF4 + O2F2 \to XeF6 + O2$ 230. $In Haber's process, 50.0 g of N_{2} (g) and 10.0 g of H_{2} (g) are mixed to produce NH_{3} (g) . What is the number of moles of NH_{3} (g) formed?$ (1) $3.33$ (2) $2.36$ (3) $2.01$ (4) $5.36$ 231. $What is the mass of the precipitate formed when 50 m L of 16.9% solution of A g N O_{3} is mixed with 50 m L of 5.8% N a C 1 solution? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5)$ (1) $3.5 g$ (2) $7 g$ (3) $14 g$ (4) $28 g$ 232. $6 g of urea (molar mass = 60 g mol^{- 1}) and 9 g of glucose (molar mass = 180 g mol^{- 1}) were dissolved in 35 g of water. The mass percent of urea and glucose is respectively$ (1) $18,12$ (2) $6,9$ (3) $12,18$ (4) $9,6$ 233. $How many gram of sodium (atomic mass 23 u) is required to prepare one mole of ethane from methyl chloride by Wurtz reaction?$ (1) $2$ (2) $23$ (3) $11.5$ (4) $46$ 234. $Dissolving 120 g of urea (mol. wt. 60) in 1000 g of water gave a solution of density 1.15 g/mL. The molarity of the solution is:$ (1) $1.78 M$ (2) $2.00 M$ (3) $2.05 M$ (4) $2.22 M$ 235. $Mass of methane required to produce 22 g of CO_{2} after complete combustion is________ g. (Given Molar mass in g mol-1 C = 12.0 H = 1.0 O = 16.0)$ 236. $Complete combustion of 3 g of ethane gives x \times 10^{22} molecules of water. The value of x is___ (Round off to the Nearest Integer) [ Use : N_{A} = 6.023 \times 10^{23}; Atomic masses in u : C : 12.0; O : 16.0; H : 1.0]$ 237. $The NaNO_{3} weighed out to make 50mL of an aqueous solution containing 70.0 mgNa^{+} per mL is ____ g. (Rounded off to the nearest integer) [Given: Atomic weight in g mol^{- 1} . Na : 23; N : 14; O : 16]$ 238. $Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at STP from the reaction of 11.5 g of zinc with excess HC1 is ______ L(Nearest integer) (Given : Molar mass of Zn is 65.4g m o l^{- 1} and Molar volume of H_{2} at STP = 22.7L)$ 239. $1 g of a carbonate (M_{2} C O_{3}) on treatment with excess HC1 produces 0.01 mol of C O_{2} . The molar mass of M_{2} C O_{3} is g m o l^{- 1} . (Nearest integer)$ 240. $The amount of calcium oxide produced on heating 150 kg limestone (75 % pure) is kg. (Nearest integer) Given: Molar mass (in gmol^{- 1}) of Ca - 40, 0 - 16, C-12$