For the neutralization between a strong and a strong base, equal number of moles of ${\mathrm{H}}^{+}$ (from acid) and $\stackrel{-}{\mathrm{O}}\mathrm{H}$ (from base) come out. For one mole of following equation can be drawn

So, 0.25 mole of ${\mathrm{H}}_2\mathrm{O}$ is produced.
So, heat released $\text{=}\left(\text{0}\text{.25}\text{×}\text{13}\text{.7}\right)\text{kcal}\text{=}\text{3}\text{.425}\text{kcal}$