For a reversible reaction $\quad A \rightleftharpoons B$, which one of the following statements is wrong from the given energy profile diagram?

• A

  Activation energy of forward reaction is greater than backward reaction
• B

  The forward reaction is endothermic
• Correct answer
  C

  The threshold energy is less than that of activation energy
• D

  The energy of activation of forward reaction is equal to the sum of heat of reaction and the energy of activation of backward reaction

Solution

where, $E_a=$ activation energy of forward reaction $E_a^{\prime}=$ activation energy of backward reaction The above energy profile diagram shows that $$ E_a>E_a^{\prime} $$ The potential energy of the product is greater than that of the reactant, so the reaction is endothermic. $$ \begin{aligned} & E_a=E_a^{\prime}+\Delta E \\ & E_t=E_a \text { or } E_t>E_a^{\prime} \end{aligned} $$

Hence, the correct answer is option: 'C'.