Question

The rate constant of a second order reaction depends upon:

• A. the initial concentration of the reactants
• B. the time elapsed from the beginning of the reaction
• C. the temperature
• D. the concentration of the products

Answer 1

The correct option is C the temperature

Assume a reaction $mA+nB\to C$
Rate law can be written as : $r=k\left[A{]}^m\right[B{]}^n$.....(1)
As we know Arrhenius equation is $k=A{e}^{-\frac{E_a}{RT}}$ ...(2)
where $k$ = rate constant, $E_a$ is the activation energy and $R$ is the gas constant.
From (1) and (2) we get,
$r=A{e}^{-\frac{E_a}{RT}}\left[A{]}^m\right[B{]}^n$
So, from this we can easily infer that rate constant only depends on the temperature irrespective of their order.