Question

Consider the cell reaction of electrochemical cell : Ni(s) + 2Ag⁺ (aq) → Ni²⁺ (aq) + 2Ag(s) and answer the following questions:

(i) Write anode and cathode half reactions.

(ii) Mention the direction of flow of electrons.

(iii) How is the electrical neutrality maintained in the solutions of the two half cells?

(iv) Write the formula for calculating standard emf of this cell.

(v) How does the emf change when the concentration of silver ions decreases?

Answer 1

For reaction:

Ni(s) + 2Ag⁺ (aq) → Ni²⁺ (aq) + 2Ag(s)

(i) Oxidation half reaction (at anode)

Ni(s) → Ni²⁺ + (aq) + 2e^–

Reduction half reaction (at cathode)

Ag⁺ (aq) + e^– → Ag(s)

(ii) The flow of electrons takes place from anode to cathode.

(iii) Salt bridge is used to maintain electrical neutrality in the solution of the two half cells.

(iv) \(E^o_{cell}=E^o_{cathode}-E^o_{anode}\)

(v) When the concentration of the cell also decreases.