Which of the given substances is used in the following applications?
I. It is used as a fire proofing material.
II. It is used for sealing gaps in laboratory apparatus.
III. It is used in making toys.

Options

A. Bleaching powder
B. Plaster of Paris
C. Baking soda
D. Washing soda

Explanation

To solve the question regarding the substances used in various applications, we will analyze each application step by step and identify the correct substance.

### Step 1: Identify the Applications
The applications mentioned are:
1. Used as a fireproofing material.
2. Used for sealing gaps in laboratory apparatus.
3. Used in making toys.

### Step 2: Analyze Each Application
- **Application I: Fireproofing Material**
- Fireproofing materials are typically substances that can withstand high temperatures and prevent fire from spreading. Common materials include plaster of Paris, which is made from gypsum and is known for its fire-resistant properties.

- **Application II: Sealing Gaps in Laboratory Apparatus**
- In laboratory settings, sealing gaps is crucial to prevent leaks and ensure safety. Plaster of Paris is often used for this purpose as it can harden and create a solid seal.

- **Application III: Making Toys**
- Many toys are made from materials that can be easily molded and shaped. Plaster of Paris is commonly used in casting toys due to its ability to take on detailed shapes when set.

### Step 3: Identify the Substance
From the analysis above, plaster of Paris (chemical formula: CaSO₄·½H₂O) fits all three applications:
1. It is used as a fireproofing material.
2. It is used for sealing gaps in laboratory apparatus.
3. It is used in making toys.

### Step 4: Conclusion
Based on the applications and the properties of the substances, the correct answer is **Plaster of Paris**.