Discuss the consequences of high enthalpy of H–H bond in terms of chemical reactivity of dihydrogen.

The ionization enthalpy of $\mathrm{H}-\mathrm{H}$ bond is very high $\left(1312 \mathrm{~kJ} \mathrm{~mol}^{-1}\right)$. This indicates that hydrogen has a low tendency to form $\mathrm{H}^{+}$ions. Its ionization enthalpy value is comparable to that of halogens. Hence, it forms diatomic molecules $\left(\mathrm{H}_{2}\right)$, hydrides with elements, and a large number of covalent bonds.

Since ionization enthalpy is very high, hydrogen does not possess metallic characteristics (lustre, ductility, etc.) like metals.