Question

Which of the following is selected as cathode for a galvanic cell set up with nickel anode?

• A. Mg
• B. Cu
• C. Al
• D. Zn

Hint:

Rule: Higher reduction potential $\rightarrow$ Cathode Lower reduction potential $\rightarrow$ Anode

Answer 1

The Correct Option is B

Concept: In a galvanic cell:
• Anode: Oxidation occurs (lower reduction potential)
• Cathode: Reduction occurs (higher reduction potential)

Step 1: Standard reduction potentials (approx.).
• Mg$^{2+}$/Mg = $-2.37$ V
• Al$^{3+}$/Al = $-1.66$ V
• Zn$^{2+}$/Zn = $-0.76$ V
• Ni$^{2+}$/Ni = $-0.25$ V
• Cu$^{2+}$/Cu = $+0.34$ V

Step 2: Given Ni is anode.
Thus, cathode must have higher reduction potential than Ni.

Step 3: Compare options.
• Mg, Al, Zn $\rightarrow$ more negative than Ni (cannot be cathode)
• Cu $\rightarrow$ higher potential than Ni (can be cathode)

Step 4: Conclusion.
Thus, copper acts as cathode. Final Answer: Option (B)