An exotic elementary reaction operates with an activation energy evaluating strictly to zero. At exa — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

By the Arrhenius equation, $k = A e^{-E_a/RT}$. If the activation energy $E_a$ is identically zero, the exponent term collapses to $e^0 = 1$. Consequently, $k = A$. This physically implies that every single collision is energetically fruitful, and the rate constant becomes entirely independent of absolute temperature. Thus, at $400 \text{ K}$, it remains permanently pinned at $1.6 \times 10^6 \text{ s}^{-1}$.