Answer
$$5.49 \mathrm{\ MeV}
$$
Work Step by Step
The energy released is
$$
\begin{aligned} Q &=-\Delta m c^{2}=-\left(m_{\mathrm{H} \mathrm{e}}-m_{\mathrm{2}}-m_{\mathrm{H} \mathrm{1}}\right) c^{2} \\ &=-(3.016029 \mathrm{u}-2.014102 \mathrm{u}-1.007825 \mathrm{u})(931.5 \mathrm{MeV} / \mathrm{u}) \\ &=5.49 \mathrm{MeV} \end{aligned}
$$
