<Dd> Hg 2 2 + + 2 Cl − ↽ − − ⇀ Hg 2 Cl 2 (s), k s p = a Hg 2 2 + a Cl − 2 = (Hg 2 2 +) ⋅ (Cl −) 2 (\ displaystyle (\ ce ((Hg2 ^ (2) +) + 2Cl ^ (-) <=> Hg2Cl2 (s))), \ qquad k_ (sp) = a_ (\ ce (Hg2 ^ (2) +)) a_ (\ ce (Cl ^ (-))) ^ (2) = (\ ce ((Hg2 ^ (2) +))) \ cdot (\ ce ((Cl ^ (-)))) ^ (2)) </Dd> <P> The Nernst equations for these half reactions are: </P> <Dl> <Dd> E 1 2 cathode = E Hg 2 2 + / Hg 0 − R T 2 F ln ⁡ 1 a Hg 2 2 + (\ displaystyle E_ ((\ frac (1) (2)) (\ text (cathode))) = E_ ((\ ce (Hg_2 ^ 2 + / Hg))) ^ (0) - (\ frac (RT) (2F)) \ ln (\ frac (1) (a_ ((\ ce (Hg2 ^ 2 +))))) \ qquad) in which E Hg 2 2 + / Hg 0 = + 0.80 V (\ displaystyle \ qquad E_ ((\ ce (Hg2 ^ 2 + / Hg))) ^ (0) = + 0.80 \ \ mathrm (V)). </Dd> <Dd> E 1 2 anode = E Hg 2 Cl 2 / Hg, Cl − 0 − R T 2 F ln ⁡ a Cl − 2 (\ displaystyle E_ ((\ frac (1) (2)) (\ text (anode))) = E_ ((\ ce (Hg2Cl2 / Hg, Cl -))) ^ (0) - (\ frac (RT) (2F)) \ ln a_ ((\ ce (Cl -))) ^ (2) \ qquad) in which E Hg 2 Cl 2 / Hg, Cl − 0 = + 0.27 V (\ displaystyle \ qquad E_ ((\ ce (Hg2Cl2 / Hg, Cl -))) ^ (0) = + 0.27 \ \ mathrm (V)). </Dd> </Dl> <Dd> E 1 2 cathode = E Hg 2 2 + / Hg 0 − R T 2 F ln ⁡ 1 a Hg 2 2 + (\ displaystyle E_ ((\ frac (1) (2)) (\ text (cathode))) = E_ ((\ ce (Hg_2 ^ 2 + / Hg))) ^ (0) - (\ frac (RT) (2F)) \ ln (\ frac (1) (a_ ((\ ce (Hg2 ^ 2 +))))) \ qquad) in which E Hg 2 2 + / Hg 0 = + 0.80 V (\ displaystyle \ qquad E_ ((\ ce (Hg2 ^ 2 + / Hg))) ^ (0) = + 0.80 \ \ mathrm (V)). </Dd>

Explain the construction and working of calomel electrode