A solution of acetone in ethanol

1.00 g of a non-electrolyte solute (molar mass 250 g mol^$$-$$1) was dissolved in 51.2 g of benzene. If the freezing point depression constant, K_f of benzene is 5.12 K kg mol^$$-$$1, the freezing point of benzene will be lowered by

A solution containing 10 g per dm³ of urea (molecular mass = 60 g mol^$$-$$1) is isotonic with a 5% solution of a nonvolatile solute is

The vapour pressure of two liquids P and Q are 80 and 60 torr, respectively. The total vapour pressure of solution obtained by mixing 3 mole of P and 2 mole of Q would be