Question

The decomposition of a hydrocarbon follows the equation $k=\left(4.5\times10^{11}s^{-1}\right)e^{-28000 K /T}.$ What will be the value of activation energy?

• A. $669 \, KJ$ $mol^{-1}$
• B. $232.79 \, KJ$ $mol^{-1}$
• C. $4.5\times10^{11} \,KJ$ $mol^{-1}$
• D. $28000 \, KJ$ $mol^{-1}$

Answer 1

Answer: (B)

Arrhenius equation, $k=Ae^{-Ea/ RT}$
Given equation is $k =\left(4.5\times10^{11}s^{-1}\right)$ $e^{-28000 K /T}$
Comparing both the equations, we get
$-\frac{E_{a}}{RT}$ $=-\frac{28000\, K }{T}$
$E_{a}$ $=28000 K\times R=28000 K\times8.314 J K^{-1}$ $ mol^{-1}$
$=232.79 \,KJ$ $mol^{-1}$