Some Basic Concepts of Chemistry PYQs Set 10 (PDF)

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Some Basic Concepts of Chemistry · Set 10 (Q271-300)
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271. $An aqueous solution containing 6.5 g of NaCl of 90 % purity was subjected to electrolysis. After the complete electrolysis, the solution was evaporated to get solid NaOH . The volume of 1 M acetic acid required to neutralise NaOH obtained above is$ (1) $2000 cm^{3}$ (2) $100 cm^{3}$ (3) $200 cm^{3}$ (4) $1000 cm^{3}$ 272. $When 20 g of CaCO_{3} is treated with 20 g of HCl, the mass of CO_{2} formed would be$ (1) $10 g$ (2) $8.8 g$ (3) $22.2 g$ (4) $20 g$ 273. $An organic compound having C, H and O has 13.13 % H, 52.14 % C and 34.73 % O . Its molar mass is 46.068 g . What are its empirical and molecular formulae?$ (1) $C_{2} H_{6} O, C_{4} H_{12} O_{2}$ (2) $CH_{3} O, C_{2} H_{6} O_{2}$ (3) $C_{2} H_{6} O, C_{2} H_{6} O$ (4) $C_{2} H_{6} O_{2}, C_{3} H_{9} O_{4}$ 274. $What is the molarity of H_{2} S O_{4} solution that has a density of 1.84 g/cc and contains 98% by mass of H_{2} S O_{4} ? (Given atomic mass of S = 32)$ (1) $4.18 M$ (2) $8.14 M$ (3) $18.4 M$ (4) $18 M$ 275. $0.6 g of urea on strong heating with NaOH evolves N H_{3} . Liberated N H_{3} will combine completely with which of the following HCl solution?$ (1) $100 mL of 0.2 NHCl$ (2) $400 mL of 0.2NHCl$ (3) $100 mL of 0.1 NHCl$ (4) $200 mL of 0.2NHCl$ 276. $What will be the answer in appropriate significant figures as a result of addition of 3.0223 and 5.041?$ (1) $80.633$ (2) $8.0633$ (3) $8.063$ (4) $806.33$ 277. $Given P = 0.0030 m, Q = 2.40 m, R = 3000 m, Significant figures in P, Q and R are respectively$ (1) $2, 2, 1$ (2) $2, 3, 4$ (3) $4, 2, 1$ (4) $4, 2, 3$ 278. $According to significant figure convention, the result obtained by adding 12.11, 18.0 and 1.012 is$ (1) $31.12$ (2) $31.1$ (3) $31$ (4) $31.122$ 279. $A compound X contains 32 % of A, 20 % of B and remaining percentage of C . Then, the empirical formula of X is (Given atomic masses of A = 64; B = 40, C = 32)$ (1) $A_{2} B C_{2}$ (2) $A B C_{3}$ (3) $A B_{2} C_{2}$ (4) $AB C_{4}$ 280. $The dimension of energy per unit volume is the same as that of$ (1) $Force$ (2) $Pressure$ (3) $Power$ (4) $Density$ 281. $The number of significant figures in 60.0001 is$ (1) $5$ (2) $6$ (3) $3$ (4) $2$ 282. $Two solution of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5M first solution + 520 ml of 1.2M second solution. What is the molarity of the final mixture ?$ (1) $2.70M$ (2) $1.344M$ (3) $1.50M$ (4) $1.20M$ 283. $The correctly reported answer of the addition of 29.4406 , 3.2 and 2.25 will have significant figures:$ (1) $3$ (2) $4$ (3) $2$ (4) $5$ 284. $The number of moles of H_{2}, which is required to produce 10 moles of NH_{3} in the following reaction is a H_{2} (g) + b NO_{2} (g) ⟶ c NH_{3} (g) + d H_{2} O (g)$ (1) $10$ (2) $20$ (3) $35$ (4) $53$ 285. $The maximum number of molecules is present in$ (1) $15 L of H_{2} gas at STP$ (2) $5 L of N_{2} gas at STP$ (3) $0.5 g of H_{2} gas$ (4) $10 g of O_{2} gas$ 286. $The total number of electrons in 18 mL of water (density = 1 g mL^{- 1}) is$ (1) $6.02 \times 10^{23}$ (2) $6.02 \times 10^{25}$ (3) $6.02 \times 10^{24}$ (4) $6.02 \times 18 \times 10^{23}$ 287. $28 gKOH is required to completely neutralise CO_{2} produced on heating 60 g of impure CaCO_{3} . The percentage purity of CaCO_{3} is approximately (molar masses of KOH and CaCO_{3} are 56 and 100 g mol^{- 1}, respectively)$ (1) $41.6$ (2) $40$ (3) $20.8$ (4) $83.3$ 288. $Equal masses of H_{2}, O_{2} and methane have been taken in a container of volume V at temperature 2 7^{o} C in identical conditions. The ratio ofthe volumes ofgases H_{2} : O_{2} : methane would be$ (1) $8:16:1$ (2) $16:8:1$ (3) $16:1: 2$ (4) $8:1: 2$ 289. $The volume of water that must be added to a mixture of 250 ml of 0.6 M HCl and 750 ml of 0.2 M HCl to obtain 0.25 M solution of HCl is:$ (1) $750 ml$ (2) $100 ml$ (3) $200 ml$ (4) $300 ml$ 290. $What should be the volume of the milk (in m^{3}) which measures 5 L?$ (1) $5 \times 1 0^{- 3} m^{3}$ (2) $5 \times 1 0^{3} m^{3}$ (3) $5 \times 10000 m^{3}$ (4) $5 \times 1 0^{6} m^{3}$ 291. $A metal oxide has the formula Z_{2} O_{3} . It can be reduced by hydrogen to give free metal and water. 0.1596 g of the metal oxide requires 6 mg of hydrogen for complete reduction. The atomic weight of the metal is$ (1) $27.9$ (2) $159.6$ (3) $79.8$ (4) $55.8$ 292. $Quantitative analysis of an organic compound (X) shows following % composition. C: 14.5%, Cl: 64.461%, H: 1.8%, (remaining is O). Empirical formula mass of the compound (X) is ____\times 1 0^{- 1} (Given molar mass in g mol^{- 1} of C: 12, H: 1, O: 16, Cl: 35.5)$ 293. $In the above reaction, 5 g of toluene is converted into benzaldehyde with 92% yield. The amount of benzaldehyde produced is ______x 1 0^{- 2} g. (Nearest integer)$ 294. $_____grams of Hydroxy propanal must be dehydrated to produce of acrolein \left if the percentage yield is . (Round off to the Nearest Integer). [Given: Atomic masses: ]$ 295. $In the given reaction, X + Y + 3 Z ⇌ XY Z_{3} if one mole of each of X and Y with 0.05 mol of Z gives compound XYZ3. (Given : Atomic masses of X, Y and Z are 10, 20 and 30 amu, respectively). The yield of XYZ3 is__________g.(Nearest integer)$ 296. $On complete combustion 0.30 g of an organic compound gave 0.20 g of carbon dioxide and 0.10 g of water. The percentage of carbon in the given organic compound is ________ (Nearest Integer)$ 297. $Chlorophyll extracted from the crushed green leaves was dissolved in water to make 2 L solution of Mg of concentration 48 ppm. The number of atoms of Mg in this solution is x \times 1 0^{20} atoms. The value of x is________. (Nearest Integer)(Given : Atomic mass of Mg is 24 g m o l^{- 1}, N_{A} = 6.02x 1 0^{23} m o l^{- 1})$ 298. $Thyroxine, the hormone has given below structure The percentage of iodine in thyroxine is %. (nearest integer) (Given molar mass in gmol^{- 1} C : 12, H : 1, O : 16, N : 14, I : 127)$ 299. $The number of N atoms is 681 g of C_{7} H_{5} N_{3} O_{6} is x \times 1 0^{21} . The value of x is_____(N_{A} = 6.02 x 1 0^{23} m o l^{- 1}) (Nearest Integer)$ 300. $9.3 g of aniline is subjected to reaction with excess of acetic anhydride to prepare acetanilide. The mass of acetanilide produced if the reaction is 100 % completed is _______\times 10^{- 1} g . (Given molar mass in (gmol^{- 1} N : 14, O : 16, C : 12, H : 1)$