The standard enthalpy of formation for methane CH4 is -74.9KJ/mol.In order to calculate average energy given out in the formation of C-H bond from this it is necessary to know which one of the following?
a] the dissociation energy of H2 and entahlpy of sublimation of carbon
b]the first four ionisation energy of carbon
c]the first four ionisation energies of carbon and electron affinity of H2
d]the dissociation energy of the hydrogen molecule,H2