To determine in which of the ions chlorine will not undergo disproportionation, we first need to understand the concept of disproportionation. Disproportionation is a type of redox reaction in which the same element is both oxidized and reduced, resulting in two different products.
### Step-by-Step Solution:
1. **Identify the Oxidation States of Chlorine:**
Chlorine can exist in various oxidation states ranging from -1 to +7. The relevant ions we will consider are:
- Cl⁻ (oxidation state -1)
- ClO₄⁻ (oxidation state +7)
- ClO₃⁻ (oxidation state +5)
- ClO₂ (oxidation state +4)
2. **Analyze Each Ion for Disproportionation:**
- **Cl⁻ (oxidation state -1):**
- Chlorine can be oxidized to higher oxidation states (0, +1, +3, +5, +7) but cannot be reduced further (it is already at the lowest oxidation state of -1). Therefore, it can only be oxidized, not reduced. Hence, it cannot undergo disproportionation.
- **ClO₄⁻ (oxidation state +7):**
- Chlorine at +7 cannot be oxidized further (as there is no oxidation state higher than +7), but it can be reduced to lower oxidation states (such as +5, +3, +1, or -1). Therefore, it can only be reduced, not oxidized. Hence, it cannot undergo disproportionation.
- **ClO₃⁻ (oxidation state +5):**
- Chlorine at +5 can be oxidized to +7 and reduced to +3, +1, or -1. Thus, it can undergo disproportionation as it can both be oxidized and reduced.
- **ClO₂ (oxidation state +4):**
- Chlorine at +4 can also be oxidized to +5 or +7 and reduced to +3, +1, or -1. Thus, it can undergo disproportionation as well.
3. **Conclusion:**
From the analysis, the ions where chlorine will not undergo disproportionation are:
- Cl⁻ (oxidation state -1)
- ClO₄⁻ (oxidation state +7)
Thus, the answer is that chlorine will not undergo disproportionation in the ions Cl⁻ and ClO₄⁻.
