Question

The rate constant, the activation energy and the Arrhenius parameter of a chemical reaction at $25^{\circ }C$ are $3.0\times 10^{-4}{s}^{-1}$ , $104.4kJmo{l}^{-1}$ and $6.0\times 10^{14}{s}^{-1}$ , respectively.
The value of the rate constant at $T\to \infty$ is

• A. $2.0\times 10^{18}{s}^{-1}$
• B. $6.0\times 10^{14}{s}^{-1}$
• C. $3.6\times 10^{30}{s}^{-1}$
• D. Infinity

Answer 1

Answer: (B)

Effect of temperature on the rate of reaction hence, rate constant $k$, can be calculated by using Arrhenius equation which is $K=A{e}^{-E_a/RT}$
given : $A=6.0\times 10^{-14}{s}^{-1}$
$E_a=104.4KJmo{l}^{-1}$
$T=\infty$
$\because K=e^{-E_a/RT}$
or $logK=logA-\frac{E_a}{2.303RT}$
At $T=\infty$
$logk-logA+\frac{E_a}{2.303R\times 100}$
$logk=logA+0$
$logk=log6\times 10^{14}$
$K=6\times 10^{14}{s}^{-1}$