If a compound AB dissociates to the extent of 75 % in an aqueous solution, the molality of the solution which shows a 2.5 K rise in the boiling point…

If a compound AB dissociates to the extent of $\displaystyle 75 \%$ in an aqueous solution, the molality of the solution which shows a $\displaystyle 2.5$ K rise in the boiling point of the solution is \_\_\_\_ molal. (Rounded-off to the nearest integer) $\displaystyle \left[\mathrm{K}_{\mathrm{b}}=0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right]$