Question

At 25°C, the heat required to dissociate 4 g hydrogen gas into free gaseous atoms is 208 kCal. Then what will be the bond energy of H-H bond?

Answer 1

Bond enthalpy is defined as amount of energy required to break one mole of bonds of a particular type between atoms in gaseous state.
For 4 g = 2 mole of H₂
E = 208 kcal
as bond energy is always for 1 mole thus bond energy of H-H will be 208/2= 104 kcal