120) 20 gm of a substance was dissolved in 500 mL of water and the osmotic pressure of the solution was found to be 600 mm of Hg at 15^oC. Determine the molecular weight of the substance:

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)

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

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:

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: