An aqueous solution contains `H^(+),Ag^(+),Fe^(2+) and Zn^(2+) ` ions . The ion that will be reduced first at cathode is .

Options

A. `H^(+)`
B. `Ag^(+)`
C. `Fe^(2+)`
D. `Zn^(2+)`

Answer

To determine which ion will be reduced first at the cathode in an aqueous solution containing \( H^+, Ag^+, Fe^{2+}, \) and \( Zn^{2+} \) ions, we need to compare their standard reduction potentials. The ion with the highest reduction potential will be reduced first.

### Step-by-Step Solution:

1. **Identify the Ions and Their Reduction Reactions**:
- \( H^+ + e^- \rightarrow \frac{1}{2} H_2 \) (Reduction potential = 0.00 V)
- \( Ag^+ + e^- \rightarrow Ag \) (Reduction potential = +0.80 V)
- \( Fe^{2+} + 2e^- \rightarrow Fe \) (Reduction potential = -0.44 V)
- \( Zn^{2+} + 2e^- \rightarrow Zn \) (Reduction potential = -0.76 V)

2. **List the Standard Reduction Potentials**:
- \( H^+ \): 0.00 V
- \( Ag^+ \): +0.80 V
- \( Fe^{2+} \): -0.44 V
- \( Zn^{2+} \): -0.76 V

3. **Compare the Reduction Potentials**:
- The highest reduction potential is for \( Ag^+ \) at +0.80 V.
- The next highest is \( H^+ \) at 0.00 V.
- Both \( Fe^{2+} \) and \( Zn^{2+} \) have negative potentials, indicating they are less likely to be reduced compared to \( H^+ \) and \( Ag^+ \).

4. **Determine the Ion Reduced First**:
- Since \( Ag^+ \) has the highest reduction potential, it will be reduced first at the cathode.

### Conclusion:
The ion that will be reduced first at the cathode is \( Ag^+ \).

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