Question

An endothermic reaction $A\to B$ have an activation energy 15 kcal/mol and the heat of reaction is 5 kcal/mol. The activation energy of the reaction $B\to A$ is:

• A. 20 kcal/mol
• B. 15 kcal/mol
• C. 10 kcal/mol
• D. zero

Answer 1

The correct option is C 10 kcal/mol

Its a Endothermic Reaction, So

$\Delta H=\left[E_{a\left(f\right)}\right]-\left[E_{b\left(f\right)}\right]$

Given, $\left[E_{a\left(f\right)}\right]=15kcal/mol$ and $\Delta H=5kcal/mol$

$\left[E_{b\left(f\right)}\right]=15-5=10kcal/mol$