Decolouration of lead and silver paints is caused due to

Options

A. sulphur dioxide
B. carbon monoxide
C. hydrogen sulphide
D. ozone

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the cause of decoloration in lead and silver paints. It is important to identify the specific agent responsible for this phenomenon.

2. **Identifying the Options**: The options provided include carbon monoxide, hydrogen sulfide, and ozone. We need to analyze which of these substances is known to cause decoloration in paints.

3. **Analyzing Hydrogen Sulfide**: Hydrogen sulfide (H₂S) is a well-known compound that can react with certain metals and pigments in paints. It is particularly known for its ability to cause discoloration and darkening of lead and silver paints.

4. **Mechanism of Decolorization**: When hydrogen sulfide comes into contact with lead and silver paints, it can lead to a chemical reaction that alters the original color of the paint. This reaction results in a darkening effect, making the paints lose their original vibrancy.

5. **Conclusion**: Based on the information gathered, it can be concluded that the decoloration of lead and silver paints is primarily caused by hydrogen sulfide.

**Final Answer**: The decoloration of lead and silver paints is caused by hydrogen sulfide.

---