Question

Which among the following species is reduced by tin easily?

• A. Iodine
• B. Iron
• C. Zinc
• D. Sodium

Hint:

A species with a more positive standard reduction potential ($\text{E}^{\circ}$) is a stronger oxidizing agent and is more easily reduced. Conversely, a species with a more negative $\text{E}^{\circ}$ is a stronger reducing agent and is more easily oxidized.

Answer 1

The Correct Option is D

Concept:
If tin acts as a reducing agent, it loses electrons and reduces another species. A substance will be reduced easily if it has a higher (more positive) standard reduction potential $\left(E^\circ\right)$. For spontaneous reaction: \[ E^\circ_{\text{cell=E^\circ_{\text{cathode-E^\circ_{\text{anode>0 \] Thus, the species with highest reduction potential will be most easily reduced by tin.
Step 1: Standard reduction potential of tin
For tin: \[ Sn^{2+}+2e^- \rightarrow Sn \] \[ E^\circ=-0.14\,V \] So tin metal can act as a reducing agent.
Step 2: Compare given options

• $I_2 + 2e^- \rightarrow 2I^- \qquad E^\circ=+0.54\,V$
• $Fe^{2+}+2e^- \rightarrow Fe \qquad E^\circ=-0.44\,V$
• $Zn^{2+}+2e^- \rightarrow Zn \qquad E^\circ=-0.76\,V$
• $Na^+ + e^- \rightarrow Na \qquad E^\circ=-2.71\,V$

Step 3: Identify easiest species to reduce
Greater positive value of $E^\circ$ means stronger tendency to gain electrons. Among all options: \[ +0.54\,V \text{ is highest} \] This corresponds to iodine.
Step 4: Check spontaneity with tin
\[ E^\circ_{\text{cell=0.54-(-0.14)=+0.68\,V \] Since $E^\circ_{\text{cell$ is positive, iodine is readily reduced by tin.
Step 5: Final Answer
The species easily reduced by tin is: \[ \boxed{I_2} \] Quick Tip:
Higher standard reduction potential $\Rightarrow$ easier reduction. Tin can reduce substances having $E^\circ$ greater than $-0.14\,V$.