Question

Give some examples of second-order reactions.

Answer 1

Second-order reaction:

1. A reaction is considered to be second-order when the order of the reaction is $2$.
2. The rate of these reactions can be calculated using either the concentration of one reactant squared or the concentration of two reactants separately.
3. Examples of Second-order reactions are - Nitrogen dioxide produces nitrogen monoxide and oxygen.

$\underset{\mathrm{Nitrogen}\mathrm{dioxide}}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Nitrogen}\mathrm{monoxide}}{\mathrm{NO}\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

4. The rate law for decomposition of nitrogen dioxide is $\mathrm{r}=\mathrm{k}{\left[{\mathrm{NO}}_2\right]}^2$

5. Hydrogen iodide decomposition - Hydrogen iodide decomposes into iodine and hydrogen.

$\underset{\mathrm{Hydrogen}\mathrm{Iodide}}{2\mathrm{HI}\left(\mathrm{g}\right)}\to \underset{\mathrm{Hydrogen}\mathrm{gas}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Iodide}\mathrm{gas}}{{\mathrm{I}}_2\left(\mathrm{g}\right)}$

6. The rate law for decomposition of hydrogen iodide is $\mathrm{r}=\mathrm{k}{\left[\mathrm{HI}\right]}^2$

7. Hydrolysis of an ester in presence of a base-

$\underset{\mathrm{Ethyl}\mathrm{acetate}}{{\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5\left(\mathrm{l}\right)}+\underset{\mathrm{Sodium}\mathrm{hydroxide}}{\mathrm{NaOH}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{acetate}}{{\mathrm{CH}}_3\mathrm{COONa}\left(\mathrm{s}\right)}+\underset{\mathrm{Ethanol}}{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right)}$

8. The rate law for hydrolysis of ester $\mathrm{r}=\mathrm{k}\left[{\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5\right]\left[\mathrm{NaOH}\right]$