Liquid Solution

A 1 molar aqueous solution of magnesium nitrate is $40 \%$ dissociated at 298 K . Calculate the osmotic pressure of the solution. $\left(R=0.0821 \mathrm{~L} \mathrm{~atm} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right)$