If the bond dissociation energies of XY, X2 and Y2 (all diatomic molecules) are in the ratio of 1 : 1 : 0.5 and ΔHf for the formation of XY is –200kJ mol–1. The bond dissociation energy of X2 will be
(a) 400kJ mol–1 (b) 300kJ mol–1 (c) 200kJ mol–1 (d) None of these
