On dissolving 0.5 g of non-volatile, non-ionic solute to 39 g of benzene, its vapour pressure decreases from 650 mm of Hg to 640 mm of Hg. The depression of the freezing point of benzene (in K) upon addition of the solute is ___. [Given data: Molar mass and molar freezing point depression of benzene is 78 g mol^-1 and 5.12 K kg mol^-1]