Question

Which of the following graphs represent exothermic reaction?

• A. (c) only
• B. (b) only
• C. (a) only
• D. (a) and (b)

Answer 1

The correct option is C (a) only

In an exothermic reaction , the reactants are at a higher energy level as compared to the products.

For exothermic reaction $\Delta H=-ve$

$\Delta H=E_a\left(forward\right)-E_a\left(backward\right)=-ve$

So,$E_a$(backward)>$E_a$(Forward)

Graph (b) - The energy of the product is greater than that of a reactant. Hence, the reaction is endothermic in nature for the forward direction.

Graph (c) - The energy of product and reactant is same. Hence, it is neither endothermic nor exothermic in nature.

Hence, option (A) is correct.