For an exothermic reaction $X \rightarrow Y$,the activation energy is $30 \ kJ \ mol^{-1}$. If the enthalpy change $(\Delta H)$ for the reaction is $-20 \ kJ \ mol^{-1}$,then the activation energy for the reverse reaction is . . . . . . $kJ \ mol^{-1}$.

For a reaction,the threshold energy is $75 \ kJ/mol$. If the internal energy of the reactants is $20 \ kJ/mol$,the activation energy (in $kJ/mol$) is

In which of the following cases is the percentage increase in rate constant maximum?

$Case$	$E_a \ (kcal/mol)$	$Temp. \ Change \ (K)$
$I$	$40$	$200 - 210$
$II$	$80$	$200 - 210$
$III$	$40$	$300 - 310$
$IV$	$80$	$300 - 310$

$A \rightarrow B$
The rate constants of the above reaction at $200 \, K$ and $300 \, K$ are $0.03 \, min^{-1}$ and $0.05 \, min^{-1}$ respectively. The activation energy for the reaction is $.... \, J$ (Nearest integer).
(Given: $\ln 10 = 2.3$,$R = 8.3 \, J \, K^{-1} \, mol^{-1}$,$\log 5 = 0.70$,$\log 3 = 0.48$,$\log 2 = 0.30$)

Activation energy is defined as:

The rate constant for the decomposition of hydrocarbons is $2.418 \times 10^{-5} \, s^{-1}$ at $546 \, K$. If the energy of activation is $179.9 \, kJ / mol$,what will be the value of the pre-exponential factor?