Certain amount of washing soda crystals are exposed to atmosphere, a loss in weight was noticed. How can you account for this ?

Explanation

**Step-by-Step Solution:**

1. **Identify the Compound**: The compound in question is washing soda, which is chemically known as sodium carbonate (Na2CO3). It exists as a crystalline solid with water of crystallization.

2. **Understand Water of Crystallization**: Washing soda crystals contain 10 molecules of water (10H2O) per formula unit of sodium carbonate. This water is integral to the structure of the crystal and is referred to as water of crystallization.

3. **Exposure to Atmosphere**: When washing soda crystals are exposed to the atmosphere, they come into contact with air, which can lead to changes in their physical state.

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