Identify $\mathrm{X}$ in the following nuclear reactions: (a) ${ }^1 \mathrm{H}+$ ${ }^9 \mathrm{Be} \rightarrow \mathrm{X}+\mathrm{n} ;$ (b) ${ }^{12} \mathrm{C}+{ }^1 \mathrm{H} \rightarrow \mathrm{X} ;$ (c) ${ }^{15} \mathrm{~N}+{ }^1 \mathrm{H} \rightarrow{ }^4 \mathrm{He}+\mathrm{X}$. Appendix F will help.
${ }^9 \mathrm{~B}$