Question

Why does the addition of sulphuric acid to water produce a conducting solution?

Answer 1

(1) Pure water consist of molecules only. It will not dissociates into ions and hence, cannot conduct electricity.

(2) By the addition of sulphuric acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$ to water, the ions from the sulphuric acid are introduced into pure water.

(3) The degree of ionization increase and due to this, water conducts electricity.

Chemical equation :

Dissociation of acidified water gives ions which are free to move and conduct electricity.

$$\begin{gathered} {\mathrm{H}}_2{\mathrm{SO}}_4\rightleftharpoons 2{\mathrm{H}}^{+}+{\mathrm{SO}}_4^{2-} \\ (\mathrm{sulphuric}(\mathrm{cation})(\mathrm{sulphate}\mathrm{ion}\left) \\ \mathrm{acid}\right) \end{gathered}$$

$$\begin{gathered} {\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{H}}^{+}+{\mathrm{OH}}^{-} \\ \left(\mathrm{water}\right)\left(\mathrm{cation}\right)\left(\mathrm{hydroxide}\right) \end{gathered}$$

So, the addition of sulphuric acid is necessary to produce a conducting solution.