Discuss the consequences of high enthalpy of H–H bond in terms of chemical reactivity of dihydrogen.
The ionization enthalpy of H–H bond is very high (1312 kJ mol–1). This indicates that hydrogen has a low tendency to form H+ ions. Its ionization enthalpy value is comparable to that of halogens. Hence, it forms diatomic molecules (H2), 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.
This is due to its small atomic size and also small bond length (74 pm) of H-H bond.