Physical Chemistry MCQ with Answers

Physical Chemistry MCQ with Answers

121) 0.15 gm of a substance, dissolved in 15 gm of solvent, was boiled at a temperature higher by 0.216^oC than that of the pure solvent. Calculate the molecular weight of the substance: (Molal elevation constant for the solvent = 2.16^oC)

Answer is:

100

Explanation:

m = (1000 x K_b x w) ⁄ (ΔT_b x W)

122) The concentration of pollutant in ppm, that has been measured at 450 mg per 150 kg of sample, is:

Answer is:

3 ppm

123) Ratio of ΔT_b⁄K_b of 6% of AB₂ and 9% of A₂B is 1 mol⁄kg in both the cases. Atomic masses of A and B are respectively:

Answer is:

40, 10

124) Van′t Hoff factors of aqueous solutions of X, Y and Z are 1.8, 0.8 and 2.5. Choose the correct option:

Answer is:

F.P.: Z < X < Y

125) The relationship between osmotic pressure at 273 K when 10 gm glucose (P1), 10 gm urea (P2) and 10 gm sucrose (P3) are dissolved in 250 mL of water:

Answer is:

P2 > P1 > P3

Explanation:

P ∝ 1⁄m

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