The energies of activation for forward and reverse reactions for A2 + B22AB 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)

Question

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) (A) 300 (B) 120 (C) 280 (D) -20

Tardigrade Admin · Accepted Answer

So, Δ HReaction=Ef-Eb = 80 - 100 = -20 Hence, (4) is correct.

$300$

$120$

$280$

$- 20$

So, $Δ H_{R e a c t i o n} = E_{f} - E_{b}$
$= 80 - 100 = - 20$
Hence, $(4)$ is correct.

300

120

280

−20

So, ΔHReaction​=Ef​−Eb​ =80−100=−20 Hence, (4) is correct.

$300$

$120$

$280$

$- 20$

So, $Δ H_{R e a c t i o n} = E_{f} - E_{b}$
$= 80 - 100 = - 20$
Hence, $(4)$ is correct.