Question

In the electrolysis of aqueous sodium chloride solution which of the half cell reaction will occur at anode?

पर्याय

• \[\ce{Na+ (aq) + e- -> Na (s); E^{Θ}_{cell} = - 2.71V}\]

• \[\ce{2H2O (l) -> O2(g) + 4H+ (aq) + 4e^- ; E^{Θ}_{cell} = 1.23V}\]

• \[\ce{H^+ (aq) + e^- -> 1/2 H2 (g); E^{Θ}_{cell} = 0.00V}\]

• \[\ce{Cl^- (aq) -> 1/2 Cl2 (g) + e^- ; E^{Θ}_{cell} = 1.36V}\]

Answer 1

\[\ce{Cl^- (aq) -> 1/2 Cl2 (g) + e^- ; E^{Θ}_{cell} = 1.36V}\]

Explanation:

During electrolysis of aqueous

\[\ce{NaCl -> Na^+ + Cl^-}\]

\[\ce{H2O -> H+ + OH-}\]

\[\ce{Na+ + e- -> Na (E^{Θ}_{cell} = - 2.71V)}\]

\[\ce{H^+ e- -> 1/2 H2 E^{Θ}_{cell} = 0.00V}\]

At cathode,

\[\ce{H2O + e- -> 1/2 H2 + OH-}\]

At anode, two reactions are possible.

\[\ce{Cl^{-} -> 1/2 Cl2 + e- ; E^{Θ}_{cell} = 1.36V}\]

\[\ce{2H2O -> O2 + 4H+ + 4e- ; E^{Θ}_{cell} = 1.23V}\]