If $8 \mathrm{g}$ of a non-electrolyte solute is dissolved in $114 \mathrm{g}$ of $\mathrm{n}-$octane to reduce its vapour pressure to $80\%,$ the molar mass (in $\mathrm{g} {\mathrm{mol}}^{-1}$) of the solute is [Given that molar mass of n-octane is $114 \mathrm{g} {\mathrm{mol}}^{-1}$]