Some Basic Concepts of Chemistry PYQs Set 6 (PDF)

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Mere Teacher · Previous Year Questions NEET Chemistry · Some Basic Concepts of Chemistry · Set 6 (Q151-180)
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151. $Dissolving 120 g of a compound of (mol. wt. 60) in 1000 g of water gave a solution of density 1.12 g/mL. The molarity of the solution is:$ (1) $1.00 M$ (2) $2.00 M$ (3) $2.50 M$ (4) $4.00 M$ 152. $The correctly reported answer of the area of rectangle which is 12.34 cm long and 1.23 cm wide is :$ (1) $15.2 m^{2}$ (2) $15.2 cm^{2}$ (3) $15.1 cm^{2}$ (4) $15.17 cm^{2}$ 153. $How many different scientific notations may be written for the result 10500 g?$ (1) $Four$ (2) $Three$ (3) $Five$ (4) $Two$ 154. $How many electrons are involved in the following redox reaction? C r_{2} O_{7}^{2-} + F e^{2 +} + C_{2} O_{4}^{2-} \to C r^{3 +} + F e^{3 +} + C O_{2} (unblanced)$ (1) $3$ (2) $4$ (3) $6$ (4) $5$ 155. $5 L of an alkane requires 25 L of oxygen for its complete combustion. If all volumes are measured at constant temperature and pressure, the alkane is:$ (1) $Butane$ (2) $Isobutane$ (3) $Ethane$ (4) $Propane$ 156. $When 22.4 L of H_{2} (g) is mixed with 11.2 L^{-} of Cl_{2} (g), each at STP, the moles of HCl (g) formed is equal to$ (1) $1 mole of HCl (g)$ (2) $2 moles of HCl (g)$ (3) $0.5 mole of HCl (g)$ (4) $1.5 moles of HCl (g)$ 157. $Aqueous HCl reacts with MnO_{2} (s) to form MnCl_{2} (aq), Cl_{2} (g) and H_{2} O (l) . What is the weight (in g) of Cl_{2} liberated when 8.7 g of MnO_{2} (s) is reacted with excess aqueous HCl solution? (Given Molar mass in gmol^{- 1} Mn = 55, Cl = 35.5, O = 16, H = 1)$ (1) $21.3$ (2) $71$ (3) $14.2$ (4) $7.1$ 158. $The minimum amount of O_{2} (g) consumed per gram of reactant is for the reaction :(Given atomic mass : Fe = 56, O=16, Mg = 24, P =31, C = 12, H = 1)$ (1) $4 Fe (s) + 3 O_{2} (g) \to 2 F e_{2} O_{3} (s)$ (2) $P_{4} (s) + 5 O_{2} (g) \to P_{4} O_{10} (s)$ (3) $C_{3} H_{8} (g) + 5 O_{2} (g) \to 3 C O_{2} (g) + 4 H_{2} O (I)$ (4) $2 Mg (s) + O_{2} (g) \to 2 MgO (s)$ 159. $A pure compound contains 2.4 g of C, 1.2 \times 10^{23} atoms of H, 0.2 moles of oxygen atoms. Its empirical formula is$ (1) $C_{2} HO$ (2) $CH_{2} O$ (3) $C_{2} H_{2} O_{2}$ (4) $CHO$ 160. $A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 ml of CO_{2} at T = 298.15 K and p = 1 bar. If molar volume of CO_{2} is 25.0 L under such condition, what is the percentage of sodium bicarbonate in each tablet? [Molar mass of NaHCO_{3} = 84 g mol^{- 1}]$ (1) $0.84$ (2) $33.6$ (3) $16.8$ (4) $8.4$ 161. $The formula of a metal oxide is . The fractions of metal that exists as and ions in that oxide are respectively$ (1) $0.083, 0.916$ (2) $0.916, 0.083$ (3) $0.88, 0.12$ (4) $0.12, 0.88$ 162. $Express the result of (0.582 + 324.65) to the appropriate number of significant figures:$ (1) $325.24$ (2) $325.23$ (3) $325.2$ (4) $325.232$ 163. $The formula of nickel oxide is Ni_{0.98} O_{1.00} . What is the approximate percentage of Ni^{+ 2} in it?$ (1) $92$ (2) $94$ (3) $96$ (4) $98$ 164. $25 mL of silver nitrate solution (1M) is added dropwise to 25 mL of potassium iodide (1. 05 M) solution. The ion(s) present in very small quantity in the solution is/are$ (1) $I^{-} only$ (2) $K^{+} only$ (3) $N O_{3}^{-} only$ (4) $A g^{+} and I^{-} both$ 165. $One litre of 0.15 M Na_{2} SO_{3} aqueous solution is mixed with 500 mL of 0.2 M K_{2} Cr_{2} O_{7} aqueous solution in acid medium. What is the number of moles of K_{2} Cr_{2} O_{7} remaining in the solution after the reaction?$ (1) $0.1$ (2) $0.0125$ (3) $0.025$ (4) $0.05$ 166. $Calculate the percent atom economy when a product of formula weight 175 u is obtained in a chemical reaction using 225 u formula weight reactant.$ (1) $70.1 %$ (2) $77.7 %$ (3) $90.5 %$ (4) $95.0 %$ 167. $The pair of compounds having metals in their highest oxidation state is:$ (1) $(MnO_{4})^{-} and C r O_{2} C l_{2}$ (2) $[F e C l_{4}]^{-} and C o_{2} O_{3}$ (3) $[Fe(CN)_{6}]^{3-} and [Cu(CN)_{4}]^{2-}$ (4) $[N i C l_{4}]^{2-} and [C o C l_{4}]^{2-}$ 168. $What amount of dioxygen (in gram) contains 1.8 \times 10^{22} molecules?$ (1) $0.960$ (2) $96.0$ (3) $0.0960$ (4) $9.60$ 169. $The statement related to law of definite proportions is$ (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) $Matter can neither be created nor destroyed.$ 170. $The decomposition of a certain mass of CaCO_{3} gave 11.2 dm^{3} of CO_{2} gas at STP. The mass of KOH required to completely neutralise the gas is$ (1) $56 g$ (2) $28 g$ (3) $42 g$ (4) $20 g$ 171. $0.12 g of an organic compound ' X' containing phosphorus on reacting with magnesia mixturc gave 0.22 g of magnesium pyrophosphate (Mg_{2} P_{2} O_{7}) . The percentage of phosphorus in the compound ' X' is \dots \dots \dots$ (1) $45.30 %$ (2) $28.70 %$ (3) $64.25 %$ (4) $51.20 %$ 172. $An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be$ (1) $CHO$ (2) $C H_{2} O$ (3) $C H_{3} O$ (4) $C H_{4} O$ 173. $To an aqueous solution containing ions such as A l^{3 +}, Z n^{2 +}, C a^{2 +}, F e^{3 +}, N i^{2 +}, B a^{2 +} and C u^{2 +} was added conc. HCl, followed by H_{2} S . The total number of cations precipitated during this reaction is/are:$ (1) $1$ (2) $3$ (3) $4$ (4) $2$ 174. $If 50 % of 1 M Na_{2} SO_{4} is dissociated in aqueous solution of density 1.2 g mL^{- 1}, what is the molality of Na^{+} ion in the solution?$ (1) $0.95$ (2) $1.89$ (3) $1.00$ (4) $2.00$ 175. $A carbon compound contains 12.8 % of carbon, 2.1 % of hydrogen and 85.1 % of bromine. The molecular weight of the compound is 187.9. Calculate the molecular formula of the compound. (Atomic weight: H = 1.008, C = 12.0, Br = 79.9)$ (1) $CH_{3} Br$ (2) $CH_{2} Br_{2} I$ (3) $C_{2} H_{4} Br_{2}$ (4) $C_{2} H_{3} Br_{3}$ 176. $Chlorine is allowed to react with excess of ammonia. In this, 1 mole of chlorine can oxidise ' Z' moles of NH_{3}, ' Z' is$ (1) $\frac{3}{8}$ (2) $\frac{8}{3}$ (3) $\frac{2}{3}$ (4) $\frac{3}{2}$ 177. $On combustion 0.210 g of an organic compound containing C, H and O gave 0.127 g H_{2} O and 0.307 g CO_{2} . The percentages of hydrogen and oxygen in the given organic compound respectively are:$ (1) $7.55, 43.85$ (2) $6.72, 53.41$ (3) $6.72, 39.87$ (4) $53.41, 39.6$ 178. $14.0 g of calcium metal is allowed to react with excess HCl at 1.0 atm pressure and 273 K. Which of the following statements is incorrect? [Given : Molar mass in gmol^{- 1} of Ca - 40, Cl - 35.5, H - 1]$ (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) $33.3 g of CaCl_{2} is produced.$ 179. $A solution is prepared by adding 2 g of "X" to 1 mole of water. Mass percent of "X" in solution is$ (1) $5%$ (2) $20%$ (3) $2%$ (4) $10%$ 180. $In which case is number of molecules of water maximum?$ (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) $1 0^{- 3} mol of water$