Pure water freezes at $$273$$ $$K$$ and $$1$$ bar. The addition of $$34.5$$ $$g$$ of ethanol to $$500$$ $$g$$ of water changes the freezing point of the solution. Use the freezing point depression constant of water as $$2$$ kg $$mo{l^{ - 1}}.$$ The figures shown below represent plots of vapor pressure $$(V.P.)$$ versus temperature $$(T).$$ [molecular weight of ethanol is $$46$$ $$g$$ $$mo{l^{ - 1}}.$$ ] Among the following, the option representing change in the freezing point is

The qualitative sketches I, II and III given below show the variation of surface tension with molar concentration of three different aqueous solutions of KCl, CH₃OH and CH₃(CH₂)₁₁ OSO$$_3^ - $$ Na⁺ at room temperature. The correct assignment of the sketches is

For a dilute solution containing 2.5 g of a non-volatile non-electrolyte solute in 100 g of water. the elevation in boiling point at 1 atm pressure is 2^oC. Assuming concentration of solute is much lower than the concentration of solvent, the vapour pressure (mm of Hg) of the solution is (take K_b = 0.76 K Kg mol^-1)

The freezing point (in ^oC) of a solution containing 0.1 g of K₃[Fe(CN)₆] (Mol. wt. 329) in 100 g of water (K_f = 1.86 K kg mol^-1) is