.Which of the following are the example of double salt?
A. `FeSO_(4)*(NH_(4))_(2)SO_(4)*6H_(2)O`
B. `CuSO_(4)*4NH_(3)*H_(2)O`
C. `K_(2)SO_(4)*Al_(2)(SO_(4))_3 .24H_(2)O`
D. ` Fe(CN)_(2)*4KCN`
Choose the correct answer

Options

A. `A and B only`
B. `A, B and D only`
C. `A and C only`
D. `B and D only`

Answer

To determine which of the given options are examples of double salts, we first need to understand what a double salt is. A double salt is a type of salt that consists of two different salts that crystallize together in a fixed ratio.

Let's analyze each option one by one:

### Step 1: Analyze Option A
**Option A: `FeSO4 * (NH4)2SO4 * 6H2O`**

- This compound consists of iron(II) sulfate and ammonium sulfate.
- Since it is a combination of two salts, it qualifies as a double salt.

**Conclusion:** Option A is a double salt.

### Step 2: Analyze Option B
**Option B: `CuSO4 * 4NH3 * H2O`**

- This compound consists of copper(II) sulfate and ammonia.
- However, this is not a double salt; it is a complex salt where ammonia acts as a ligand to the copper ion.

**Conclusion:** Option B is not a double salt.

### Step 3: Analyze Option C
**Option C: `K2SO4 * Al2(SO4)3 * 24H2O`**

- This compound consists of potassium sulfate and aluminum sulfate.
- Since it is a combination of two salts, it qualifies as a double salt.

**Conclusion:** Option C is a double salt.

### Step 4: Analyze Option D
**Option D: `Fe(CN)2 * 4KCN`**

- This compound consists of iron(II) cyanide and potassium cyanide.
- This is also a complex salt where cyanide ions act as ligands surrounding the iron ion.

**Conclusion:** Option D is not a double salt.

### Final Answer
The correct options that are examples of double salts are **A and C**.