1.80 g of solute A was dissolved in $62.5 \mathrm{~cm}^3$ of ethanol and freezing point of the solution was found to be 155.1 K . The molar mass of solute A is $\_\_\_\_$ $\mathrm{g} \mathrm{mol}^{-1}$.
[Given: Freezing point of ethanol is 156.0 K . Density of ethanol is $0.80 \mathrm{~g} \mathrm{~cm}^{-3}$. Freezing point depression constant of ethanol is $2.00 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ ]