When `ClO_3^-`, changes to`CI^-`

Options

A. It gains six electrons
B. It gains four electrons
C. It loses six electrons
D. It gains three electrons

Answer

To determine what happens when \( \text{ClO}_3^- \) changes to \( \text{Cl}^- \), we need to analyze the oxidation states of chlorine in both species.

### Step-by-Step Solution:

1. **Identify the oxidation state of chlorine in \( \text{ClO}_3^- \)**:
- Let the oxidation state of chlorine be \( x \).
- The oxidation state of oxygen is typically \(-2\).
- The overall charge of the ion is \(-1\).
- The equation can be set up as:
\[ x + 3(-2) = -1 \]
- Simplifying this gives:
\[ x - 6 = -1 \]
\[ x = +5 \]
- Thus, the oxidation state of chlorine in \( \text{ClO}_3^- \) is \( +5 \).

2. **Identify the oxidation state of chlorine in \( \text{Cl}^- \)**:
- In \( \text{Cl}^- \), the oxidation state of chlorine is \( -1 \).

3. **Determine the change in oxidation state**:
- The change in oxidation state from \( +5 \) to \( -1 \) indicates a reduction.
- The change can be calculated as:
\[ +5 \text{ to } -1 = 5 - (-1) = 5 + 1 = 6 \]
- Therefore, chlorine is reduced by gaining 6 electrons.

4. **Conclusion**:
- When \( \text{ClO}_3^- \) changes to \( \text{Cl}^- \), chlorine undergoes reduction by accepting 6 electrons.