The mass defect in a particular reaction is 0.4 g. The amount of energy liberated is n × 10^7 kWh, where n= ____. ( speed of light =3 × 10^8 m / s )

The mass defect in a particular reaction is $\displaystyle 0.4$ g . The amount of energy liberated is $\displaystyle n \times 10^7 \mathrm{kWh}$, where $\displaystyle n=$ $\displaystyle \_\_\_\_$. $$\left(\text { speed of light }=3 \times 10^8 \mathrm{~m} / \mathrm{s}\right) $$