Question

The rate constants for decomposition of acetaldehyde have been measured over the temperature range $700-1000\, K$. The data has been analysed by plotting In $k$ vs $\frac{10^{3}}{ T }$ graph. The value of activation energy for the reaction is ____ $kJ\, mol ^{-1}$. (Nearest integer) (Given : $R =8.31\, J \, K ^{-1}\, mol ^{-1}$ )

Answer 1

$\ln k =\ln A -\frac{ Ea }{10^{3} RT } \times 10^{3}$
$= nA +\frac{10^{3}}{ T }\left[-\frac{ Ea }{10^{3} RT }\right]$
From the graph
$\frac{- Ea }{10^{3} \times R }=-18.5$
$Ea =153.735\, kJ / mol$
$\sim 154$