Question

The rate constant, the activation energy and the Arrhenius parameter of a chemical reaction at ${25}^{\circ }C$ are $x,10xkJ/mol$ and $2x{s}^{-1}$. The value of the rate constant as $T\to \infty$ is:

• A. $x{s}^{-1}$
• B. $2x{s}^{-1}$
• C. $\infty$
• D. $10x{s}^{-1}$

Answer 1

The correct option is B $2x{s}^{-1}$

A change in temperature changes only the rate constant of the reaction whilst other parameters like activation energy and arrhenius parameter remain the same.
At ${25}^o$C,
Rate constant $k=A{e}^{-\frac{E_a}{RT}}$
$x=2x{e}^{-\frac{10x}{R\times 298}}$
At $T=\infty$
$k=2x{e}^{-\frac{E_a}{R\infty }}=2x{s}^{-1}$
$(T\to \infty$, $\frac{1}{T}\to 0)$