Question

The decomposition of formic acid on a gold surface follows first order kinetics and specific rate constants are $5.5\times {10}^{-4}{s}^{-1}$ and $9.2\times {10}^{-3}{s}^{-1}$ at ${140}^{o}C$ and ${185}^{o}C$ respectively. Energy of activation is:

• A. $98.46Jmo{l}^{-1}$
• B. $98.46kJmo{l}^{-1}$
• C. $23.7Jmo{l}^{-1}$
• D. $23.7kJmo{l}^{-1}$

Answer 1

The correct option is B $98.46kJmo{l}^{-1}$

$log\frac{k_2}{k_1}=\frac{E_a}{2.303R}[\frac{1}{T_1}-\frac{1}{T_2}]$

$log\frac{9.2\times {10}^{-3}}{5.5\times {10}^{-4}}=\frac{E_a}{2.303\times 8.314}[\frac{1}{413}-\frac{1}{458}]$

$E_a=98.46kJmo{l}^{-1}$