Question

Which of the following reactions exhibit minimum standard reduction potential?

• A. \(2\text{H}^+_{\text{(aq)}} + 2\text{e}^- \rightarrow \text{H}_{2\text{(g)}}\)
• B. \(\text{F}_{2\text{(g)}} + 2\text{e}^- \rightarrow 2\text{F}^-_{\text{(aq)}}\)
• C. \(\text{Li}^+_{\text{(aq)}} + \text{e}^- \rightarrow \text{Li}_{\text{(s)}}\)
• D. \(\text{Cl}_{2\text{(g)}} + 2\text{e}^- \rightarrow 2\text{Cl}^-_{\text{(aq)}}\)

Hint:

Alkali metals usually have very negative reduction potentials, so they are strong reducing agents in elemental form.

Answer 1

The Correct Option is C

Concept:
Standard reduction potential tells the tendency of a species to get reduced. More positive value means greater tendency to gain electrons. More negative value means lower tendency to get reduced.

Step 1: Recall standard reduction potential values.

• \(E^\circ\) for \(\text{H}^+/\text{H}_2 = 0.00\,\text{V}\)
• \(E^\circ\) for \(\text{F}_2/\text{F}^- \) is highly positive
• \(E^\circ\) for \(\text{Cl}_2/\text{Cl}^- \) is also positive
• \(E^\circ\) for \(\text{Li}^+/\text{Li}\) is highly negative

Step 2: Identify minimum standard reduction potential.
The most negative value corresponds to the minimum standard reduction potential. That is: \[ \text{Li}^+_{\text{(aq)}} + \text{e}^- \rightarrow \text{Li}_{\text{(s)}} \] Hence, the correct answer is:
\[ \boxed{(C)\ \text{Li}^+_{\text{(aq)}} + \text{e}^- \rightarrow \text{Li}_{\text{(s)}}} \]