Q21.32 P - Chemistry: Molecular Nature Of Matter And Change

Question

A voltaic cell is constructed with a ${\text{Cu/Cu}}^{\text{2 + }}$ half-cell and an${\text{Ni/Ni}}^{\text{2 + }}$ half-cell. The nickel electrode is negative. 

(a) Write balanced half-reactions and the overall reaction. 

(b) Diagram the cell, labeling electrodes with their charges and showing the directions of electron flow in the circuit and of cation and anion flow in the salt bridge

Step-by-Step Solution

Answer

a)   ${\text{Ni + Cu}}^{\text{2 + }}\to {\text{Ni}}^{\text{2 + }}\text{ + Cu}$ 

b) 

Step 1: Given in the question are as

1. ${\text{Ni/Ni}}^{\text{2 + }}$Half cell
2. ${\text{Cu/Cu}}^{\text{2 + }}$ Half cell
3. The nickel electrode is negative, i.e., it is an anode.

Step 2: Determining Half-reactions that are balanced and the overall reaction

Anode:  $\text{Ni}\to {\text{Ni}}^{\text{2 + }}{\text{ + 2e}}^{\text{ - }}$

Cathode:  ${\text{Cu}}^{\text{2 + }}{\text{ + 2e}}^{\text{ - }}\to \text{Cu}$

Overall impression:  ${\text{Ni + Cu}}^{\text{2 + }}{\text{ + 2e}}^{\text{ - }}\to {\text{Ni}}^{\text{2 + }}{\text{ + 2e}}^{\text{ - }}\text{ + Cu}$

 ${\text{ = Ni + Cu}}^{\text{2 + }}\to {\text{Ni}}^{\text{2 + }}\text{ + Cu}$

Step 3: Diagram of the cell with labelling