Mohr's salt is

Options

A. `FeS_(2).7H_(2)O`
B. `FeSO_(4)(NH_(4))_(2)SO_(4).6H_(2)O`
C. `Fe_(2)(SO_(4))_(3)(NH_(4))_(2)SO_(4).24H_(2)O`
D. `K_(2)SO_(4).Fe_(2)(SO_(4))_(3).24H_(2)O`

Answer

### Step-by-Step Solution:

1. **Definition of Mohr's Salt**:
- Mohr's salt is an inorganic compound that is classified as a double salt. It is composed of two different cations and two different anions.

2. **Chemical Formula**:
- The chemical formula for Mohr's salt is \( \text{(NH}_4)_2\text{Fe(SO}_4)_2 \cdot 6\text{H}_2\text{O} \). This indicates that it contains ammonium ions, iron(II) ions, sulfate ions, and water of crystallization.

3. **Ionic Composition**:
- In the formula, you can identify:
- Two ammonium ions (\( \text{NH}_4^+ \))
- One iron ion (\( \text{Fe}^{2+} \))
- Two sulfate ions (\( \text{SO}_4^{2-} \))
- Six water molecules (\( 6\text{H}_2\text{O} \))

4. **Properties**:
- Mohr's salt is known for its use in analytical chemistry, particularly in redox titrations and as a source of iron(II) ions.

5. **Identification of Mohr's Salt**:
- When dissolved in water, Mohr's salt dissociates into its constituent ions, which can be detected in solution.

6. **Conclusion**:
- Therefore, Mohr's salt is a double salt with the formula \( \text{(NH}_4)_2\text{Fe(SO}_4)_2 \cdot 6\text{H}_2\text{O} \).