CBSE Class 10 Answered

Electrolysis is the passage of a current through an ionic substance in molten or dissolved state in a suitable solvent, resulting in chemical reactions at the electrodes and separation of materials.

The main components required to achieve electrolysis are :

• Electrolyte : a substance containing free ions that carry current  . No electrolysis occurs in solid state.
• Electric current is carried by electrons in the external circuit.
• Two electrodes: conductors which provide the physical interface between the electric circit and the electrolyte.

Electrodes of graphite,metals and semiconductor  material are widely used.

The Process of electrolysis

The  process of electrolysis is the interchange of atoms and ions by the removal or addition of electrons from the external circuit. For example, in the electrolysis of brine to produce hydrogen and chlorine, the products are gaseous. These gaseous products bubble from the electrolyte and are collected.

2 NaCl + 2 H₂O ? 2 NaOH + H₂ + Cl₂

A liquid containing mobile ions (electrolyte) is produced by:

• Reaction of an ionic compound with a solvent (like water) to produce mobile ions
• An ionic compound is fused by heating.

Each electrode attracts ions that are  oppositely chargred. Positively charged ions (cations) move towards the electron-providing (negative) cathode, whereas negatively charged ions (anions) move towards the positive anode.

At the electrodes, electrons are absorbed or released by the atoms and ions.

Those atoms that gain or lose electrons to become charged ions pass into the electrolyte.

Those ions that gain or lose electrons to become uncharged atoms separate from the electrolyte. The formation of uncharged atoms from ions is called discharging.