For the reaction A+B→C+D ΔH=−20 kJ mol−1 . The activation energy of the forward reaction is 85kJ mol–1. The activation energy for backward reaction is
65 kJ mol−1
85 kJ mol−1
40 kJ mol−1
105 kJ mol−1
ΔH = Ea(forward)−Ea(backward)
−20=(85)−Ea(backward)
Ea(backward)=105KJ.mol−1