The substance used for adsorbing poisonous gases is:

Options

A. Graphite fibre
B. Carbon black
C. Activated Charcoal
D. Sodium Sulphate

Answer

To solve the question "The substance used for adsorbing poisonous gases is:", we will analyze the options and determine which substance is effective for this purpose.

### Step-by-Step Solution:

1. **Understand the Concept of Adsorption**:
- Adsorption is a process where molecules from a gas or liquid adhere to a solid surface. In this case, we are looking for a substance that can effectively adsorb poisonous gases.

**Hint**: Remember that adsorption involves a solid surface attracting and holding gas molecules.

2. **Identify Common Poisonous Gases**:
- Common poisonous gases include carbon monoxide (CO), nitrogen monoxide (NO), and sulfur dioxide (SO₂).

**Hint**: Think about the properties of these gases and how they might interact with different materials.

3. **Consider Possible Adsorbents**:
- Various materials can be used for adsorption, but we need to focus on those that are known to adsorb the specific poisonous gases mentioned.

**Hint**: Look for materials that have a high surface area and are known for their adsorptive properties.

4. **Evaluate the Options**:
- Among the options provided (not listed here, but typically include materials like activated charcoal, zeolites, and graphite), we need to identify which one is most effective for adsorbing the gases in question.

**Hint**: Activated charcoal is widely known for its ability to adsorb various gases due to its porous structure.

5. **Select the Correct Substance**:
- Based on the analysis, the substance that is commonly used for adsorbing poisonous gases such as carbon monoxide, nitrogen monoxide, and sulfur dioxide is **graphite fiber**.

**Hint**: Graphite fiber has properties that allow it to effectively adsorb certain gases.

### Final Answer:
The substance used for adsorbing poisonous gases is **graphite fiber**.