In the reduction of dichromate by Fe(II), the number of electrons involed per chronium atom is :-

Options

A. 2
B. 1
C. 3
D. 4

Answer

To determine the number of electrons involved per chromium atom in the reduction of dichromate by Fe(II), we can follow these steps:

### Step 1: Write the reduction half-reaction for dichromate
The reduction of dichromate ion (Cr₂O₇²⁻) can be represented as:
\[ \text{Cr}_2\text{O}_7^{2-} + 6e^- + 14H^+ \rightarrow 2\text{Cr}^{3+} + 7H_2O \]

### Step 2: Analyze the oxidation states
In the dichromate ion (Cr₂O₇²⁻), the oxidation state of chromium (Cr) is +6. After reduction, the chromium ions (Cr³⁺) have an oxidation state of +3.

### Step 3: Calculate the change in oxidation state
The change in oxidation state for each chromium atom can be calculated as follows:
- Initial oxidation state of Cr: +6
- Final oxidation state of Cr: +3
- Change in oxidation state: +6 to +3 = 3 (reduction)

### Step 4: Determine the number of electrons transferred per chromium atom
Since each chromium atom undergoes a change of 3 in its oxidation state, it means that each chromium atom accepts 3 electrons during the reduction process.

### Conclusion
Thus, the number of electrons involved per chromium atom in the reduction of dichromate is **3**.

### Final Answer
The number of electrons involved per chromium atom is **3**.

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