If the charge on a capacitor is increased by 2C , the energy stored...

Energy stored in a capacitor is given by $E = \dfrac{{Q}^{2}}{2C}$.

Let initial charge be ${Q}_{0}$.

Then, $1 . 44\left({Q}_{0}^{2}2C\right) = \dfrac{{\left({Q}_{0} + 2\right)}^{2}}{2C}$

$⇒ 1 . 2{Q}_{0} = {Q}_{0} + 2$

${Q}_{0} = \dfrac{2}{0 . 2} = 10C$