If at 298K the bond energies of C – H, C – C, C = C and H – H bonds are respectively 414, 347, 615 and 435kJ mol–1, the value of enthalpy change for the reaction H2C = CH2(g) + H2(g) → H3C – CH3(g)at 298K will be
(a) +250kJ
(b) –250kJ
(c) +125kJ
(d) –125kJ.
