Question

What is K in a first-order reaction?

Answer 1

1. In first-order reactions, the rate of the reaction depends on the concentration of only one of the reactants.
2. The rate law for the first-order reaction is given as, $rate=k\left[A\right]$, where $\mathrm{k}=\mathrm{rate}\mathrm{constant};\left[\mathrm{A}\right]=\mathrm{concentration}\mathrm{of}\mathrm{the}\mathrm{reactant}$.
3. The integrated rate law can be given as, $\left[A\right]={\left[A\right]}_o{e}^{-kt}$, graphically it shows an exponential relation between the concentration and time.
4. The rate constant of the first-order reaction is given as, $k=\frac{0.693}{t_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}}$. Thus, the unit of the rate constant is ${\sec }^{-1}$.