Question

In a hypothetical reaction $X\to Y$, the activation energy for the forward and backward reactions are $15$ and $9kJmo{l}^{-1}$ respectively. The potential energy of $X$ is $10kJmo{l}^{-1}$. Which of the following statements is/are correct?
(i) The threshold energy of the reaction is $25kJ$
(ii) The potential energy of $Y$ is $16kJ$
(iii) Heat of reaction is $6kJ$
(iv) The reaction is endothermic.

• A. Only (i)
• B. Only (i) and (ii)
• C. Only (ii) and (iii)
• D. All are correct

Answer 1

The correct option is D All are correct

$E_{af}=15kJ/mol$, $E_{ab}=9kJ/mol$

• $\Delta H=E_{af}-E_{ab}=6kJ$

• Potential energy of $Y=$ Potential energy of $X+$ $\Delta H$

$=16$ kJ

• $\Delta H$ is positive, the reaction is endothermic

• Threshold energy= potential energy of $X+$ $E_{af}$

$=10+15=25$ kJ

Option D is Correct.