When `SO_2` is passed through an aqueous solution of `I_2` , it becomes colourless . This is due to

Options

A. bleaching reaction of `SO_2`
B. formation of `HIO_2`
C. combination of `SO_2 and I_2`
D. formation of `NHO_3`

Answer

To solve the question, "When SO2 is passed through an aqueous solution of I2, it becomes colorless. This is due to," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- When sulfur dioxide (SO2) is introduced to an aqueous solution of iodine (I2), a chemical reaction occurs. We need to identify the products of this reaction.

2. **Identifying the Products**:
- The reaction between SO2 and I2 in the presence of water (H2O) leads to the formation of sulfuric acid (H2SO4) and hydrogen iodide (HI). The balanced chemical equation for this reaction can be represented as:
\[ SO_2 + I_2 + H_2O \rightarrow H_2SO_4 + 2HI \]

3. **Analyzing the Color of the Products**:
- Sulfuric acid (H2SO4) is a colorless liquid. Hydrogen iodide (HI) is also colorless in solution. Therefore, the products formed from the reaction do not impart any color to the solution.

4. **Conclusion**:
- Since the original solution of iodine (I2) is colored (typically brown), the formation of colorless products (H2SO4 and HI) results in the solution becoming colorless. Thus, the color change is due to the reaction between SO2 and I2, leading to the formation of colorless compounds.

### Final Answer:
The solution becomes colorless due to the formation of sulfuric acid (H2SO4) and hydrogen iodide (HI) from the reaction between SO2 and I2.

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