Section E: Answer the case-based question given below.
37.a.iii. B. Give reasons:
i. Why do ionic compounds in the solid state not conduct electricity?
ii. What happens at the cathode when electricity is passed through an aqueous solution of sodium chloride?
ii. What happens at the cathode when electricity is passed through an aqueous solution of sodium chloride?
iii.B. Reasons:
i. Ionic compounds in the solid state do not conduct electricity.
In the state, ionic compounds have a rigid crystal lattice structure where the ions are fixed in place. Since the ions cannot move freely, there are no charged particles available to carry an electric current, and therefore, ionic compounds do not conduct electricity in this state.
ii. What happens at the cathode when electricity is passed through an aqueous solution of sodium chloride?
At the cathode (negative electrode), occurs. In an aqueous solution of sodium chloride, water is more easily reduced than sodium ions due to their reduction potentials. Therefore, water is reduced to hydrogen gas and hydroxide ions:
\(2H_2O\) + \(2e^−\) → \(H_2\)(g) + \(2OH^−\)(aq)
Thus, gas is produced at the cathode when electricity is passed through an aqueous solution of sodium chloride.