Molal depression constant for a solvent is 4.0 K k g m o l - 1 . The depression in the freezing point of the solvent for 0.03   m o l   k g - 1 solution of K 2 S O 4 is: (Assume complete dissociation of the electrolyte)

Step-by-step solution

Depression in Freezing Point = Δ T f Δ T f = i × k f × m Molality = 0.03   m o l / k g i = 3 ;    k f = 4   K   k g / m o l Δ T f = 3 × 4 × 0.03 = 0.36   K