Chemistry - Chemical Kinetics Question with Solution | TestHub

(A) False

A catalyst lowers activation energy and increases the rate constant.

A decrease in temperature reduces $k$ for both catalyzed and uncatalyzed reactions, but the catalyst effect is not "nullified" in a strict sense $\to$ False

(B) False

For a zero-order reaction:

$Rate=k$

But $k$ depends on temperature (Arrhenius equation), so the rate changes with temperature $\to$ False

(C) True

For $A\rightleftharpoons B$, $\Delta H=0$:

An increase in temperature increases the fraction of molecules with energy $\ge E_a$ for both directions equally $\to$ True

(D) False

The exponential factor $e^{-E_a/RT}$ represents the fraction of molecules having energy $\ge E_a$, not collision frequency $\to$ False