Question

The activation energy of the forward reaction and backward reaction decreases by $30kcal$ then which of the following statement is correct?

• A. $\Delta H$ will remain constant.
• B. $\Delta H$ will decrease.
• C. $\Delta H$ will increase.
• D. The reaction will be exothermic.

Answer 1

The correct option is A $\Delta H$ will remain constant.

$\Delta H=E_{af}-E_{ab}$.
So if Activation energy of the forward reaction and backward reaction decreases by 30kcal then

$\Delta H=[E_{af}+30]-[E_{ab}+30]$

$\Delta H=E_{af}-E_{ab}$.

So $\Delta H$will remain same.