The bond dissociation energies of X2,Y2 and XY are in the ratio of 1:0.5:1. ΔH for the formation of XY is −200 kJ mol⁻¹. The bond dissociation energy of X2 will be:
A. 800 kJ mol⁻¹
B. 200 kJ mol⁻¹
C. 400 kJ mol⁻¹
D. 100 kJ mol⁻¹