In ionic compounds with certain metals, hydrogen exists as the hydride ion, H-. Determine the electron affinity of hydrogen; that is, Delta H for the process H(g) + e- = H-(g). To do so, the bond energy of H2(g) -812 kJ/mol NaH for the lattice energy of NaH(s) and -57 kJ/mol NaH for the enthalpy of formation of NaH(s)