Question

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

$6.0 \times 10^{14} \, s^{-1}$

Answer 2

Effect of temperature on the rate of reaction hence, rate constant $k$, can be calculated by using Arrhenius equation which is $K=Ae^{-E_{a}/RT}$ given : $A= 6.0\times 10^{-14}\,s^{-1}$ $E_{a}=104.4\,KJ\,mol^{-1}$ $T=\infty$ $\because K=e^{-E_{a}/ RT}$ or $log\,K=log \,A-\frac{E_{a}}{2.303\,RT}$ At $T=\infty$ $log\, k - log\, A+\frac{E_{a}}{2.303\,R\times100}$ $log\,k=log\, A+0$ $log\,k=log\,6\times10^{14}$ $K=6\times10^{14}s^{-1}$