A metal rod is dipped in a solution of its ions. Its electrode potential is independent of — Electrochemistry Chemistry Question

💡 Solution & Explanation

Step 1 - Fundamental Definition of Electrode Potential For the reduction half-reaction $\ce{M^{n+}(aq) + n e^{-} <=> M(s)}$, the Nernst equation gives: $$E = E^\circ + \frac{2.303 RT}{nF} \log[\ce{M^{n+}}]$$ Step 2 - Discussion of Parameters Influencing Electrode Potential Analyzing the Nernst equation: 1. **Nature of the metal:** $E^\circ$ is a characteristic property unique to each metal. ✓ (depends) 2. **Temperature of the solution:** $T$ appears in the pre-logarithmic term $\frac{RT}{nF}$. ✓ (depends) 3. **Concentration of the solution:** $[\ce{M^{n+}}]$ is inside the logarithm. ✓ (depends) 4. **Area of the metal exposed:** Does NOT appear anywhere in the Nernst equation. Electrode potential is an **intensive property** — its value depends on the chemical identity, concentration, and temperature, not on the physical geometry of the electrode. Step 3 - Evaluation of Options and Conclusion * **Option (A)** is incorrect — potential depends on temperature ($T$). * **Option (B)** is incorrect — potential depends on concentration ($[\ce{M^{n+}}]$). * **Option (C)** is correct — potential is **independent** of surface area exposed. * **Option (D)** is incorrect — potential depends on the nature of the metal ($E^\circ$). $$\text{Correct Answer: } \boxed{\text{C}}$$