Elevation in boiling point for 1.5 molal solution of glucose in water is 4 K. The depression in freezing point for 4.5 molal solution of glucose in water is 4 K. The ratio of molal elevation constant to molal depression constant (K_b/K_f) is _________.

1.2 mL of acetic acid is dissolved in water to make 2.0 L of solution. The depression in freezing point observed for this strength of acid is 0.0198$$^\circ$$C. The percentage of dissociation of the acid is ___________. (Nearest integer)

[Given : Density of acetic acid is 1.02 g mL^$$-$$1, Molar mass of acetic acid is 60 g mol^$$-$$1, K_f(H₂O) = 1.85 K kg mol^$$-$$1]

2.5 g of protein containing only glycine (C₂H₅NO₂) is dissolved in water to make 500 mL of solution. The osmotic pressure of this solution at 300 K is found to be 5.03 $$\times$$ 10^$$-$$3 bar. The total number of glycine units present in the protein is ____________.

(Given : R = 0.083 L bar K^$$-$$1 mol^$$-$$1)

The vapour pressures of two volatile liquids A and B at 25$$^\circ$$C are 50 Torr and 100 Torr, respectively. If the liquid mixture contains 0.3 mole fraction of A, then the mole fraction of liquid B in the vapour phase is $${x \over {17}}$$. The value of x is ______________.