What is the freezing point depression constant of a solvent, \( 50 \, \mathrm{g} \) of which contain \( 1 \, \mathrm{g} \) non-volatile solute (molar mass \( 256 \, \mathrm{g\,mol^{-1}} \)) and the decrease in freezing point is \( 0.40 \, \mathrm{K} \)?
