Mohr's salt is a

Options

A. Normal salt
B. Acid salt
C. Basic salt
D. Double salt

Explanation

### Step-by-Step Solution:

1. **Identify the Chemical Formula**:
Mohr's Salt is a chemical compound with the formula \( \text{(NH}_4\text{)}_2\text{Fe(SO}_4\text{)}_2 \cdot 6\text{H}_2\text{O} \). This indicates that it contains ammonium ions, iron(II) ions, sulfate ions, and water molecules.

2. **Understanding the Composition**:
The formula can also be expressed as \( \text{(NH}_4\text{)}_2\text{SO}_4 \cdot \text{FeSO}_4 \cdot 6\text{H}_2\text{O} \). This shows that Mohr's Salt is composed of two different salts: ammonium sulfate and iron(II) sulfate, along with water of crystallization.

3. **Classifying the Type of Salt**:
Mohr's Salt is classified as a **double salt**. A double salt is formed when two different salts crystallize together in a fixed ratio. In this case, it consists of both ammonium sulfate and iron(II) sulfate.

4. **Distinguishing from Other Types of Salts**:
It is important to differentiate between simple salts, double salts, and complex salts.
- **Simple Salt**: Contains only one type of salt (e.g., NaCl).
- **Double Salt**: Contains two different salts (e.g., Mohr's Salt).
- **Complex Salt**: Contains complex ions (e.g., \( \text{K}_4[\text{Fe(CN)}_6] \)).

5. **Conclusion**:
Therefore, Mohr's Salt is a double salt, which is a combination of ammonium sulfate and iron(II) sulfate, and is often used in various chemical applications.