Question

Listed in the table are forward and reverse rate constants for the reaction $2NO\left(g\right)\rightleftharpoons N_2\left(g\right)+O_2\left(g\right)$
$\begin{array}{ccc}Temperature\left(K\right)& K_f\left(M^{-1}{s}^{-1}\right)& k_r\left(M^{-1}{s}^{-1}\right)\\ 1400& 0.29& 1.1\times {10}^{-6}\\ 1500& 1.3& 1.4\times {10}^{-5}\end{array}$
Is the reaction endothermic or exothermic?

• A. Exothermic
• B. Endothermic
• C. Can't say anything
• D. None of these

Answer 1

The correct option is A Exothermic

$k_r$ increase more than $k_f,$ this means that $E_a$ (reverse) is greater than $E_a$ (forward).
The reaction is exothermic when $E_a$ (reverse)> $E_a$ (forward).