On heating gypsum above 393 K, the product formed is

Options

A. `2(CaSO_(4))H_(2)O`
B. `CaSO_(4)(1)/(2)H_(2)O`
C. `CaSO_(4)H_(2)O`
D. Dead bumt plaster

Answer

To solve the question regarding the product formed when gypsum is heated above 393 K, we will follow these steps:

### Step 1: Identify Gypsum
Gypsum is chemically known as calcium sulfate dihydrate, which has the formula:
\[ \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \]

### Step 2: Heating Gypsum
When gypsum is heated above 393 K, it undergoes a dehydration reaction. This means that the water molecules associated with the gypsum will be removed.

### Step 3: Write the Dehydration Reaction
The dehydration of gypsum can be represented by the following chemical equation:
\[ \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \xrightarrow{\text{heat}} \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} + \frac{3}{2}\text{H}_2\text{O} \]

### Step 4: Identify the Product
The product formed after heating gypsum is calcium sulfate hemihydrate, which is commonly known as Plaster of Paris. The reaction can be simplified to:
\[ \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \rightarrow \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} + \text{H}_2\text{O} \]

### Step 5: Conclusion
When gypsum is heated above 393 K, the product formed is:
**Calcium sulfate hemihydrate (Plaster of Paris)**.

### Final Answer
The correct answer is **dead burnt plaster**.

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