Some Basic Concepts of Chemistry PYQs Set 9 (PDF)

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Some Basic Concepts of Chemistry · Set 9 (Q241-270)
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241. $In Dumas' method for estimation of nitrogen 0.4 g of an organic compound gave 60 mL of nitrogen collected at 300 K temperature and 715 mm Hg pressure. The percentage composition of nitrogen in the compound is (Given: Aqueous tension at 300 K = 15 mmHg)$ (1) $15.71 %$ (2) $17.46 %$ (3) $7.85 %$ (4) $20.95 %$ 242. $Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is Given: Molar mass of Mg is 24 g mol^{- 1}$ (1) $0.24 mg$ (2) $235.7 g$ (3) $2.444 g$ (4) $236 mg$ 243. $The emperical formula of a compound is C_{2} H_{5} O and its vapour density is 45 . What is the molecular formula of the compound?$ (1) $C_{2} H_{5} O$ (2) $C_{6} H_{13} O_{3}$ (3) $C_{4} H_{10} O_{2}$ (4) $C_{6} H_{15} O_{3}$ 244. $Which of the following chemical reactions depicts the oxidizing behaviour of H_{2} S O_{4} ?$ (1) $2HI + H2SO4 \to I2 + SO2 + 2H2O$ (2) $Ca(OH)2 + H2SO4 \to CaSO4 + 2H2O$ (3) $NaCl + H2SO4 \to NaHSO4 + HCl$ (4) $2PCl5 + H2SO4 \to 2POCl3 + 2HCl + SO2Cl2$ 245. $The molecular formula of a commercial resin used for exchanging ions in water softening is C_{8} H_{7} S O_{3} Na (Mol. wt. 206). What would be the maximum uptake of C a^{2 +} ions by the resin when expressed in mole per gram resin?$ (1) $\frac{1}{103}$ (2) $\frac{1}{206}$ (3) $\frac{2}{309}$ (4) $\frac{1}{412}$ 246. $The average molecular weight of the air which has 21 % of O_{2} and 79 % of N_{2}, is$ (1) $44.8 0$ (2) $100$ (3) $14.4$ (4) $28.8$ 247. $Molality (m) of 3 M aqueous solution of NaCl is : (Given : Density of solution = 1.25 g mL^{- 1}, Molar mass in gmol^{- 1} : Na - 23, Cl - 35.5)$ (1) $1.9 m$ (2) $3.85 m$ (3) $2.79 m$ (4) $2.90 m$ 248. $500 mL of a glucose solution contains 6.02 \times 1 0^{22} molecules. The concentration of the solution is$ (1) $0.1 M$ (2) $1.0 M$ (3) $0.2 M$ (4) $2.0 M$ 249. $Specific volume of cylindrical virus particle is 6.02 \times 1 0^{- 2} cc / g whose radius and length are 7 Å and 10 Å respectively if N_{A} = 6.02 \times 1 0^{23}, find molecular weight of virus.$ (1) $15.4 kg/mol$ (2) $1.54 \times 1 0^{4} k g / m o l$ (3) $3.08 \times 1 0^{4} kg/mol$ (4) $3.08 \times 1 0^{3} kg/mol$ 250. $100 mL of 0.2 M acetic acid is completely neutralised using a standard solution of NaOH . The volume of ethane obtained at STP after complete electrolysis of the resulting solution is$ (1) $11.2 L$ (2) $2.24 L$ (3) $0.224 L$ (4) $22.4 L$ 251. $For the reaction, Fe_{2} O_{3} + 3 CO \to 2 Fe + 3 CO_{2}, the volume of carbon monoxide required to reduce one mole of ferric oxide is$ (1) $67.2 dm^{3}$ (2) $11.2 dm^{3}$ (3) $22.4 dm^{3}$ (4) $44.8 dm^{3}$ 252. $Find the formula weight of reactants if the formula weight of product is 54 u and the percent atom economy is 75 .$ (1) $24 u$ (2) $30 u$ (3) $72 u$ (4) $80 u$ 253. $When KMnO_{4} acts as an oxidising agent and ultimately forms MnO_{4}^{2-}, MnO_{2}, Mn_{2} O_{3} and Mn^{2 +}, then the number of electrons transferred per molecule of KMnO_{4} in each case respectively, is:$ (1) $4, 3, 1, 5$ (2) $1, 5, 3, 7$ (3) $1, 3, 4, 5$ (4) $3, 5, 7, 1$ 254. $One mole of oxygen gas at STP is equal to$ (1) $6.022 \times 10^{23} molecules of oxygen$ (2) $6.022 \times 10^{23} atoms of oxygen$ (3) $32 g of oxygen$ (4) $both a and c$ 255. $Suppose the elements X and Y combine to form two compounds X Y_{2} and X_{3} Y_{2} . When 0.1 mole of X Y_{2} weighs 10 g and 0.05 mole of X_{3} Y_{2} weighs 9 g, the atomic weights o f X and Y are$ (1) $40, 30$ (2) $60, 40$ (3) $20, 30$ (4) $30, 20$ 256. $Two oxides of a X contain 50 % and 40 % of non-metal respectively. If the formula of the first oxide is XO_{2} . Then the formula of second oxide is$ (1) $X_{2} O_{3}$ (2) $X_{2} O_{5}$ (3) $XO_{3}$ (4) $X_{2} O$ 257. $An alloy of metals X and Y weighs 12 g and contains atoms X and Y in the ratio of 2 : 5 . The percentage of metal X in the alloy is 20 by mass. If the atomic mass of X is 40 amu what is the atomic mass of metal Y ?$ (1) $64 amu$ (2) $32 amu$ (3) $60 amu$ (4) $50 amu$ 258. $The molecular weight of O_{2} and S O_{2} are 32 and 64 respectively. At 15 C and 150 mmHg pressure, one litre of O_{2} contains N ’ molecules. The number of molecules in two litres of S O_{2} under the same conditions of temperature and pressure will be$ (1) $N l 2$ (2) $N$ (3) $2 N$ (4) $4 N$ 259. $20 mL of Fe^{2 +} solution of certain concentration has completely reacted with 20 mL of 0.01 M K_{2} Cr_{2} O_{7} in acidic medium. If 20 mL of same Fe^{2 +} solution has reacted completely with 20 mL of KMnO_{4} solution in acid medium, the molarity of KMnO_{4} solution is$ (1) $0.01 M$ (2) $0.12 M$ (3) $0.10 M$ (4) $0.012 M$ 260. $What is the amount of water formed by combustion of 1.6 g methane?$ (1) $3.2 g$ (2) $16 g$ (3) $6.2 g$ (4) $3.6 g$ 261. $The average molar mass of chlorine is 35.5 g mol^{- 1} . The ratio of^{35} Cl to^{37} Cl in naturally occurring chlorine is close to$ (1) $01 : 01$ (2) $02 : 01$ (3) $3 : 01$ (4) $04 : 01$ 262. $At 300 K and 1 atmospheric pressure, 10 mL of hydrocarbon required 55 mL of O_{2} for complete combustion and 40 mL of CO_{2} is formed. The formula of the hydrocarbon is :$ (1) $C_{4} H_{10}$ (2) $C_{4} H_{6}$ (3) $C_{4} H_{7} Cl$ (4) $C_{4} H_{8}$ 263. $The number of units, which are used to express concentration of solutions from the following is _______. Mass percent, Mole, Mole fraction, Molarity, ppm, Molality.$ 264. $0.5 g of an organic compound on combustion gave 1.46 g of CO_{2} and 0.9 g of H_{2} O . The percentage of carbon in the compound is . (Nearest integer) [Given: Molar mass (in ((gmol^{- 1}) C : 12, H : 1, O : 16)$ 265. $Reaction of B r_{2} with N a_{2} C O_{3} in aqueous solution gives sodium bromide and sodium bromate with evolution of C O_{2} gas. The number of sodium bromide molecules involved in the balanced chemical equation is$ 266. $0.01 mole of an organic compound (X) containing 10 % hydrogen, on complete combustion produced 0.9 gH_{2} O . Molar mass of (X) is gmol^{- 1} .$ 267. $The hydrocarbon (X) with molar mass 80 g mol^{- 1} and 90 % carbon has \dots . . degree of unsaturation.$ 268. $10 mL of gaseous hydrocarbon on combustion gives 40 mL of CO_{2} (g) and 50 mL of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is______$ 269. $If 5 moles of B a C l_{2} is mixed with 2 moles of N a_{3} P O_{4}, the maximum number of moles of B a_{3} (P O_{4})_{2} formed is__________(Nearest integer)$ 270. $When 0, 01 mol of an organic compound containing 60 % carbon was burnt completely, 4.4 g of CO_{2} was produced. The molar mase of compound is_______g mol^{- 1} (Nearest integer)$