
So, ΔHReaction =Ef−Eb =80−100=−20 Hence, (D) is correct.
JEE Main 2007 — Chemistry Physical Chemistry
The energies of activation for forward and reverse reactions for A2+B2⇌2AB are 180 kJ mol−1 and 200 kJ mol−1 respectively. The presence of catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol−1. The enthalpy change of the reaction (A2+B2⟶2AB) in the presence of catalyst will be (in kJ mol−1 )
Held on 30 Apr 2007 · Verified 6 Jul 2026.
300
120
280
20
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