Which of the following salts exis (s) as decahydrated crystals?

Options

A. Washing soda
B. Glauber's salt
C. Epson salt
D. Grypsum salt

Answer

To determine which of the given salts exist as decahydrated crystals, we need to analyze the chemical formulas of each salt and check for the presence of 10 water molecules (10 H2O) in their hydrated forms.

### Step-by-Step Solution:

1. **Understanding Decahydrated Crystals**:
- A decahydrated crystal contains 10 molecules of water (10 H2O) associated with each formula unit of the salt.

2. **Analyzing Each Salt**:
- **A. Washing Soda**:
- Chemical formula: Na2CO3·10H2O
- This indicates that washing soda has 10 water molecules.
- **Conclusion**: Washing soda is a decahydrated crystal.

- **B. Gobbler Salt**:
- Chemical formula: Na2SO4·10H2O
- This also shows that gobbler salt has 10 water molecules.
- **Conclusion**: Gobbler salt is a decahydrated crystal.

- **C. Epsom Salt**:
- Chemical formula: MgSO4·7H2O
- This indicates that Epsom salt has only 7 water molecules.
- **Conclusion**: Epsom salt is not a decahydrated crystal.

- **D. Gypsum Salt**:
- Chemical formula: CaSO4·2H2O
- This shows that gypsum salt has only 2 water molecules.
- **Conclusion**: Gypsum salt is not a decahydrated crystal.

3. **Final Conclusion**:
- The salts that exist as decahydrated crystals are:
- **Washing Soda (Na2CO3·10H2O)**
- **Gobbler Salt (Na2SO4·10H2O)**

### Summary of Answer:
The salts that exist as decahydrated crystals are Washing Soda and Gobbler Salt.