Question

To carry out the so-called ‘electrolysis of water’ sulphuric acid is added to water.

How does the addition of sulphuric acid produce a conducting solution?

Answer 1

Electrolysis of water

• Acidified water using a small amount of diluted sulphuric acid. Since water is a non-electrolyte, the addition of sulphuric acid makes it a conductor of electricity.
• Dilute sulphuric acid and not dilute nitric or hydrochloric acid is used as the nitrate ions or chloride ions may interfere with the reactions
• When we add sulphuric acid, Ions will be produced due to the dissociation of acidified water.

$$\begin{gathered} {\mathrm{H}}_2{\mathrm{SO}}_4\rightleftharpoons 2{\mathrm{H}}^{+}+{{\mathrm{SO}}_4}^{-2} \\ {\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{H}}^{+}+{\mathrm{OH}}^{-} \end{gathered}$$

• ${\mathrm{H}}^{+}$Hydrogen ions, being the only positively charged ions, migrate to the cathode.
• ${\mathrm{OH}}^{-}$and ${{\mathrm{SO}}_4}^{-2}$are the two anions migrate towards the anode.

Hence, Due to the migration of these ions, the solution becomes conducting