Question

Brine is electrolysed by using inert electrodes. The reaction
at anode is .................
(a) Cl⁻ (aq) → 1/2 Cl₂ (g) + e⁻ ; Eϴ꜀ₑₗₗ = 1.36 V
(b) 2H₂O(l) → O₂ (g) + 4H⁺ + 4e⁻; Eϴ꜀ₑₗₗ = 1.23 V
(c) Na⁺ (aq)+ e⁻ → Na (s); Eϴ꜀ₑₗₗ = 2.71 V
(d) H⁺ (aq) + e⁻ → 1/2 H₂ (g) ;Eϴ꜀ₑₗₗ = 0.00 V

Answer 1

${\huge\bf{\mid{\overline{\underline{Answer}}}\mid}}$

• (d) H⁺ (aq) + e⁻ → 1/2 H₂ (g) ;Eϴ꜀ₑₗₗ = 0.00 V

Answer 2

The reaction at anode is :

Cl⁻ (aq) → 1/2 Cl₂ (g) + e⁻ ; Eϴ꜀ₑₗₗ = 1.36 V

• Electrolysis of brine solution is a process of decomposition of NaCl solution using electrical energy.

• Anode is positive, hence it attracts negative hydroxide ions (from H2O) and Cl⁻ ions (from NaCl)

• But preferentially chloride ion gets oxidized because it is present in appreciable amount.

• Chloride ions get oxidized by electron loss to chlorine molecules.