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 can follow these steps:

### Step-by-Step Solution:

1. **Identify Gypsum**:
Gypsum is chemically known as calcium sulfate dihydrate, represented as CaSO₄·2H₂O.

2. **Understand the Heating Process**:
When gypsum is heated, it undergoes a dehydration reaction. This means that water molecules are removed from the gypsum structure.

3. **Heating Above 393 K**:
Upon heating gypsum above 393 K, it decomposes into calcium sulfate hemihydrate (CaSO₄·1/2H₂O) and water. The reaction can be represented as:
\[ \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \rightarrow \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} + \frac{3}{2}\text{H}_2\text{O} \]

4. **Identify the Product**:
The product formed, calcium sulfate hemihydrate, is commonly known as plaster of Paris. When it is further heated or treated, it can also be referred to as dead burnt plaster.

5. **Select the Correct Answer**:
From the options given, the correct answer is "dead burnt plaster," which corresponds to the product formed when gypsum is heated above 393 K.

### Final Answer:
The product formed on heating gypsum above 393 K is **dead burnt plaster**.

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