Question

Give reasons for the following:

Electrolysis is considered to be an endothermic reaction.

Answer 1

• Electrolysis occurs by passing electricity through aqueous solutions of salts.
• $\underset{\mathrm{Sodium}\mathrm{chloride}\mathrm{solution}}{2\mathrm{NaCl}\left(\mathrm{aq}\right)}\stackrel{\mathrm{electricity}}{\to }2\underset{\mathrm{Sodium}}{\mathrm{Na}\left(\mathrm{s}\right)}+\underset{\mathrm{Chlorine}}{{\mathrm{Cl}}_2\left(\mathrm{g}\right)}$
• In the above reaction sodium chloride solution is broken into sodium and chlorine gas by passing electricity through it.
• Endothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products.
• During these reactions, a bond is formed and energy is absorbed from the surroundings giving a cooling effect.
• Since electrolysis requires electrical energy to occur, it is considered to be an endothermic reaction.