How many molecules of water are there in the formula of simple alum ?

Options

A. 4
B. 6
C. 24
D. 10

Explanation

To determine how many molecules of water are present in the formula of simple alum, we can follow these steps:

### Step 1: Identify the Chemical Formula of Simple Alum
The chemical formula for simple alum, specifically potash alum, is given as:
\[ K_2SO_4 \cdot Al_2(SO_4)_3 \cdot 24H_2O \]

### Step 2: Analyze the Formula
In the formula, we can see that the term \( 24H_2O \) indicates the presence of water molecules associated with the alum.

### Step 3: Count the Water Molecules
From the formula, it is clear that there are 24 water molecules (H2O) present in the structure of potash alum.

### Conclusion
Therefore, the number of molecules of water in the formula of simple alum is **24**.

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