JEE Chemistry Practice Question

On dissolving $0.5 \mathrm{~g}$ of a non-volatile non-ionic solute to $39 \mathrm{~g}$ of benzene, its vapor pressure decreases from $650 \mathrm{~mm} \mathrm{Hg}$ to $640 \mathrm{~mm} \mathrm{Hg}$. What is the depression of freezing point of benzene (in $\mathrm{K}$ ) upon addition of the solute? (Given data: Molar mass and the molal freezing point depression constant of benzene are $78 \mathrm{~g}$ $\mathrm{mol}^{-1}$ and $5.12 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$, respectively)