Question

Explain the electrolysis of water.

Answer 1

1. Electrolysis of water is the process of decomposition of hydrogen and oxygen gas when an electric current is passed through them.
2. Water is a weak electrolyte that cannot be ionized.
3. So to ionize it and make water an electric conductor small quantity of sulphuric acid is added and this water is called acidulated water.
4. The copper rods are immersed in this acidulated water in a trough. Then the copper rods are connected to the battery and a plug key by conducting wire.
5. The copper rod is connected to a positive terminal is called a positive electrode or anode and develops a positive potential.
6. Similarly, the copper rod is connected to a negative terminal is called a negative electrode or cathode and develops a negative potential.

6. Acidulated water contains hydrogen ions and oxygen ions.

7. Hydrogen ions are positively charged so they move toward the negative electrode and get accumulated over it similarly oxygen ions are negatively charged so they move towards the positive electrode and get accumulated over it.

8. Hydrogen and oxygen are gases that can be collected by the downward displacement of water in an inverted glass jar.

9. The chemical equation of dissociation of water into ions is

10. $$\begin{gathered} {\mathrm{H}}_2\mathrm{O}\to 2{\mathrm{H}}^{+}+{{\mathrm{O}}_2}^{-} \\ \left(\mathrm{Water}\right)(\mathrm{Hydrogen}\mathrm{ion})(\mathrm{Oxygen}\mathrm{ion}) \end{gathered}$$