Question

The reduction potential for the reaction, $Mg^{2+} + 2e^{-} \rightleftharpoons Mg(s)$ depends on:

• A. Temperature
• B. The concentration of $Mg^{2+}$ ions
• C. The length of magnesium plate
• D. Whether it acts as cathode or anode in cell reaction

Answer 1

Answer: (A), (B)

A, B

Answer 2

The reduction potential for $Mg^{2+} + 2e^{-} \rightleftharpoons Mg(s)$ is described by the Nernst equation: $E = E^{\circ} + \frac{RT}{2F} \ln [Mg^{2+}]$. This equation explicitly shows dependence on Temperature (T) and the concentration of $Mg^{2+}$ ions ($[Mg^{2+}]$). Electrode potential is an intensive property, so it does not depend on the physical dimensions (like length) of the electrode. The role of an electrode (cathode or anode) in a cell is determined by its potential, not a factor that influences the potential itself.