MHTCET 16 Apr 2026 Shift 2 Paper

Concept:The Arrhenius equation relates the rate constant $k$ to activation energy $E_a$, and a higher $k$ means a faster reaction.Explanation:The rate constant is given by $k = A e^{-E_a / RT}$.A reaction proceeds more rapidly when the value of $k$ increases.The value of $k$ increases when the term $e^{-E_a / RT}$ becomes larger.This happens when the exponent $-\frac{E_a}{RT}$ becomes less negative.If $E_a$ decreases, the fraction $\frac{E_a}{RT}$ becomes smaller.Hence, $-\frac{E_a}{RT}$ is less negative, so $e^{-E_a / RT}$ increases.Consequently, $k$ increases, and the reaction becomes faster.Decreasing $T$ makes the exponent more negative, which lowers $k$.Decreasing $A$ also lowers $k$, and a decrease in $k$ itself slows the reaction.Therefore, only a decrease in activation energy $E_a$ makes the reaction proceed more rapidly.Answer:Decrease in $E_a$, i.e. Option C.