Pure sodium chloride is not hydroscopic but common salt gets wet in rainy season ? Why so ?

Explanation

### Step-by-Step Solution:

1. **Understanding Hygroscopic Substances**:
- Hygroscopic substances are those that can absorb moisture from the air. This property allows them to become wet when exposed to humid conditions.

2. **Pure Sodium Chloride (NaCl)**:
- Pure sodium chloride is a crystalline solid that does not have the ability to absorb moisture from the air. This is because it is free from impurities that could enhance its hygroscopic nature.

...