Question

The activation energies for forward and backward reactions in a chemical reaction are 30.5 and 45.4 kJ mol${}^{-1}$ respectively. The reaction is:

• A. Exothermic
• B. Endothermic
• C. Neither exothermic nor endothemic
• D. Independent of temperature

Answer 1

The correct option is A Exothermic

$E_f=30.5kJmo{l}^{-1},E_b=45.4kJmo{l}^{-1}$
Now,
$\Delta H=E_f-E_b$

$\Delta H=30.5-45.4$

$\Delta H=-14.9kJ$$mo{l}^{-1}$

$\Delta H<0$

Thus reaction is exothermic because heat is evolved during the reaction.
Option A is the correct answer.