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 1: Identify the Halogens
The halogens we need to consider are:
- Fluorine (F2)
- Chlorine (Cl2)
- Bromine (Br2)
- Iodine (I2)

### Step 2: Analyze the Reaction of Each Halogen with Water
1. **Fluorine (F2)**:
- Reaction: F2 + H2O → HF + 1/2 O2
- Oxidation States:
- F2 (0) → HF (-1) and O2 (+1)
- This indicates that fluorine is not undergoing disproportionation since it only changes from 0 to -1.

2. **Chlorine (Cl2)**:
- Reaction: Cl2 + H2O → HCl + HOCl
- Oxidation States:
- Cl2 (0) → HCl (-1) and HOCl (+1)
- Chlorine is undergoing disproportionation as it changes from 0 to -1 and +1.

3. **Bromine (Br2)**:
- Reaction: Br2 + H2O → HBr + HOBr
- Oxidation States:
- Br2 (0) → HBr (-1) and HOBr (+1)
- Bromine also undergoes disproportionation.

4. **Iodine (I2)**:
- Reaction: I2 + H2O → No reaction at room temperature.
- Therefore, iodine does not oxidize water.

### Step 3: Conclusion
From the analysis:
- Fluorine (F2) oxidizes water at room temperature without undergoing disproportionation.
- Chlorine (Cl2) and Bromine (Br2) undergo disproportionation.
- Iodine (I2) does not react.

Thus, the answer is **Fluorine (F2)**.

### Final Answer
Fluorine (F2) is the halogen that oxidizes water at room temperature but does not undergo disproportionation into it.

---