A chemical system is in equilibrium. Addition of a catalyst would result in — Chemical Equilibrium Chemistry Question

💡 Solution & Explanation

\textbf{Correct options: A, B, C} A catalyst provides an alternative reaction pathway with a lower activation energy ($E_a$). Key effects: \begin{enumerate} \item \textbf{(A) Rate of forward reaction increases} --- Lower $E_a$ means more reactant molecules have enough energy to cross the barrier. \checkmark \item \textbf{(B) Rate of reverse reaction increases} --- The catalyst lowers $E_a$ for the reverse step by the \emph{same} amount. Both rates increase equally. \checkmark \item \textbf{(C) New reaction pathway is provided} --- This is the definition of catalysis: an alternative mechanism with lower $E_a$. \checkmark \item \textbf{(D) Heat evolved is NOT changed} --- A catalyst does not alter the energies of reactants or products. $\Delta H$ is determined only by the thermodynamic state of reactants and products, not the path. \texttimes \end{enumerate} \textbf{Why equilibrium position is unchanged:} Since both forward and reverse rates increase by the same factor, the ratio $k_f/k_r = K_c$ is unaffected. Equilibrium is reached \emph{faster} but at the same position.