Which one of the following is true for an exothermic reaction $A \rightleftharpoons B$, if $E_f$ and $E_b$…
Which one of the following is true for an exothermic reaction $A \rightleftharpoons B$, if $E_f$ and $E_b$ are the activation energies of forward and backward reactions respectively?
$E_f>E_b$
$E_f=E_b$
$E_f=-E_b$
$E_f < E_b$
Solution
Activation energy for the forward reaction, $E_f$ and the activation energy for the backward reaction, $E_b$ are related to the enthalpy of the reaction by the equation.
$\Delta_r H=E_f-E_b$
For exothermic reaction
$\begin{aligned}
\Delta_r H & < 0 \\
E_b & >E_f
\end{aligned}$