8.30 :   Depict the galvanic cell in which the reaction Zn(s) + 2Ag+(aq) → Zn2++(aq) + 2Ag(s) takes place, further show:
(i) which of the electrode is negatively charged,
(ii)the carriers of the current in the cell, and (iii) the individual reaction at each electrode.

NEETprep Answer:
The galvanic cell corresponding to the given redox reaction can be represented as:

(i) Zn electrode is negatively charged because at this electrode, Zn oxidizes to Zn2+  and the leaving electrons accumulate on this electrode.
(ii) Ions are the carriers of current in the cell.
(iii) The reaction taking place at Zn electrode can be represented as:


And the reaction taking place at Ag electrode can be represented as:


(iv) In aqueous solutions,CuCl2  ionizes to give Cu2+ and Cl-ions as:


On electrolysis, either of Cu2+ ions or H2O molecules can get reduced at the cathode. But the reduction potential of Cu2+ is more than that of H2Omolecules.

Cu2+aq+2e-Cuaq;  E°=+0.34VH2Ol+2e-H2g+2OH-;  E°=-0.83V
Hence, Cu2+ ions are reduced at the cathode and get deposited.
Similarly, at the anode, either of Cl- or H2O is oxidized. The oxidation potential of H2O is higher than that of Cl-.
2Cl-aqCl2g+2e-;  E°=-1.36V2H2OlO2g+4H+aq+4e-;  E°=-1.23V

But oxidation of H2O molecules occurs at a lower electrode potential than that of Cl- ions because of over-voltage (extra voltage required to liberate gas). As a result, Cl- ions are oxidized at the anode to liberate Cl2 gas.