Which one of the following oxidises water to oxygen with large evolution of heat ?

Options

A. Chlorine
B. Bromine
C. Iodine
D. Fluorine

Explanation

To determine which element oxidizes water to oxygen with a large evolution of heat, we will analyze the reactivity of the halogens with water.

### Step 1: Analyze the reactivity of each halogen with water
- **Chlorine (Cl2)**: When chlorine reacts with water, it forms hydrochloric acid (HCl) and hypochlorous acid (HOCl). This reaction does not produce oxygen gas.

- **Bromine (Br2)**: Similar to chlorine, bromine reacts with water to form hydrobromic acid (HBr) and hypobromous acid (HOBr). This reaction also does not produce oxygen gas.

- **Iodine (I2)**: Iodine reacts with water to form hydroiodic acid (HI) and hypoiodous acid (HOI). Again, no oxygen gas is produced in this reaction.

### Step 2: Evaluate the reaction of Fluorine with water
- **Fluorine (F2)**: Fluorine is a very strong oxidizing agent. When it reacts with water, it oxidizes water to oxygen gas (O2) and forms hydrofluoric acid (HF). The reaction can be represented as:

\[ 2H2O + 2F2 \rightarrow O2 + 4HF \]

This reaction releases a significant amount of heat, indicating a large evolution of heat.

### Conclusion
Based on the analysis, the element that oxidizes water to oxygen with a large evolution of heat is **Fluorine (F2)**.

### Final Answer
**Fluorine (F2)** oxidizes water to oxygen with a large evolution of heat.

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