What do you mean by Hygroscopic compound.

Answer

### Step-by-Step Text Solution:

1. **Definition of Hygroscopic Compounds**:
- Hygroscopic compounds are substances that have the ability to attract and hold water molecules from the surrounding environment.

2. **Mechanism of Water Attraction**:
- These compounds can attract moisture either through **absorption** or **adsorption**.
- **Absorption**: This is the process where the compound takes in water, resulting in a change in its physical state.
- **Adsorption**: This is the process where water molecules adhere to the surface of the compound without being absorbed.

3. **Examples of Hygroscopic Compounds**:
- Common examples include:
- **Anhydrous Copper(II) Sulfate (CuSO4)**: This compound can absorb water and turn into hydrated copper sulfate.
- **Quicklime (Calcium Oxide, CaO)**: It readily absorbs moisture from the air, forming calcium hydroxide.
- **Anhydrous Sodium Carbonate (Na2CO3)**: This compound can also attract moisture from the environment.

4. **Significance**:
- Hygroscopic compounds are important in various applications, including desiccants (substances that absorb moisture) and in chemical reactions where moisture control is essential.