Which halogen oxidizes water at room temperature but does not undergo disproportionation into it?

Options

A. `F_(2)`
B. `Cl_(2)`
C. `Br_(2)`
D. `I_(2)`

Explanation

To solve the question "Which halogen oxidizes water at room temperature but does not undergo disproportionation into it?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand Disproportionation Reaction**:
- A disproportionation reaction is a type of redox reaction where the same species is both oxidized and reduced. This means that one part of the molecule loses electrons (is oxidized) while another part gains electrons (is reduced).

2. **Analyze the Halogens**:
- We need to consider the four main halogens: fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) and their reactions with water.

3. **Fluorine Reaction with Water**:
- When fluorine reacts with water, it forms hydrogen fluoride (HF) and oxygen (O2):
\[ 2 \text{F}_2 + 2 \text{H}_2\text{O} \rightarrow 4 \text{HF} + \text{O}_2 \]
- In this reaction, fluorine oxidizes water but does not undergo disproportionation because it does not have both oxidation and reduction occurring in the same species.

4. **Chlorine Reaction with Water**:
- Chlorine reacts with water to form hydrochloric acid (HCl) and hypochlorous acid (HOCl):
\[ \text{Cl}_2 + \text{H}_2\text{O} \rightarrow \text{HCl} + \text{HOCl} \]
- Here, chlorine is both oxidized (to HOCl) and reduced (to HCl), indicating that this is a disproportionation reaction.

5. **Bromine Reaction with Water**:
- Bromine reacts with water to form hydrobromic acid (HBr) and hypobromous acid (HOBr):
\[ \text{Br}_2 + \text{H}_2\text{O} \rightarrow \text{HBr} + \text{HOBr} \]
- Similar to chlorine, bromine also undergoes both oxidation and reduction, thus it is a disproportionation reaction.

6. **Iodine Reaction with Water**:
- Iodine does not react with water under normal conditions at room temperature, meaning it does not oxidize water or undergo disproportionation.

7. **Conclusion**:
- Among the halogens, only fluorine oxidizes water at room temperature without undergoing a disproportionation reaction. Therefore, the answer to the question is **Fluorine (F)**.

### Final Answer:
**Fluorine oxidizes water at room temperature but does not undergo disproportionation into it.**