Question

For a given half cell, \( \text{Al}^{3+} + 3e^- \rightarrow \text{Al} \) on increasing the concentration of aluminium ion, the electrode potential will

• A. No change
• B. First increase then decrease
• C. Increase
• D. Decrease

Hint:

In electrochemical cells, increasing the concentration of the reactant increases the electrode potential.

Answer 1

The Correct Option is C

For the half reaction \( \text{Al}^{3+} + 3e^- \rightarrow \text{Al} \), the electrode potential is governed by the Nernst equation. As the concentration of \( \text{Al}^{3+} \) increases, the reaction will shift, leading to an increase in the electrode potential. This is because a higher concentration of the reactant (\( \text{Al}^{3+} \)) leads to a greater driving force for the reaction.
\[ E = E^0 - \frac{0.059}{3} \log \left[ \frac{1}{[\text{Al}^{3+}]} \right] \] Thus, increasing the concentration of \( \text{Al}^{3+} \) results in an increase in the electrode potential.