Which of the following elements does not show disproportionation tendency?

Options

A. Cl
B. Br
C. F
D. I

Explanation

To determine which of the following elements does not show disproportionation tendency—Chlorine, Bromine, Fluorine, and Iodine—we need to understand what disproportionation reactions are and analyze the oxidation states of each element.

### Step-by-Step Solution:

1. **Understanding Disproportionation Reactions**:
- Disproportionation reactions involve a single substance being both oxidized and reduced in the same reaction. This means that the substance must have at least two different oxidation states.

2. **Analyzing the Given Elements**:
- The elements in question are all halogens: Chlorine (Cl), Bromine (Br), Fluorine (F), and Iodine (I).

3. **Oxidation States of Halogens**:
- **Chlorine**: Can exhibit oxidation states of -1, +1, +3, +5, and +7.
- **Bromine**: Can exhibit oxidation states of -1, +1, +3, +5, and +7.
- **Iodine**: Can exhibit oxidation states of -1, +1, +3, +5, and +7.
- **Fluorine**: Primarily exhibits an oxidation state of -1. It does not have higher oxidation states because it is the most electronegative element and cannot lose electrons.

4. **Identifying Disproportionation Tendency**:
- Chlorine, Bromine, and Iodine can undergo disproportionation because they can exist in multiple oxidation states. For example, if Chlorine is in the +5 oxidation state, it can be reduced to +3 and oxidized to +7.
- Fluorine, however, cannot undergo disproportionation because it only exists in the -1 oxidation state and cannot be oxidized further or reduced.

5. **Conclusion**:
- Based on the analysis, Fluorine does not show a disproportionation tendency because it lacks the ability to exist in multiple oxidation states.

### Final Answer:
Fluorine does not show disproportionation tendency.