The poisonous gas that comes out with petrol burning in a car is

Options

A. `CH_4`
B. `C_2H_6`
C. `CO_2`
D. CO

Explanation

To solve the question regarding the poisonous gas that comes out with petrol burning in a car, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the combustion of petrol**: When petrol (which is primarily composed of hydrocarbons) burns, it reacts with oxygen (O2) in the air. This reaction is known as combustion.

2. **Identify the products of complete combustion**: In the presence of sufficient oxygen, the complete combustion of hydrocarbons like petrol produces carbon dioxide (CO2) and water (H2O).
- Reaction: Hydrocarbon + O2 → CO2 + H2O

3. **Identify the products of incomplete combustion**: If there is insufficient oxygen available for the combustion process, incomplete combustion occurs. This can lead to the formation of carbon monoxide (CO) in addition to carbon dioxide.
- Reaction: Hydrocarbon + O2 (limited) → CO + H2O

4. **Determine the nature of the gases produced**:
- Carbon dioxide (CO2) is not considered poisonous in typical concentrations, although it can be harmful in high concentrations.
- Carbon monoxide (CO), however, is a poisonous gas that can be lethal even in small amounts because it binds with hemoglobin in the blood, preventing oxygen transport.

5. **Conclude the answer**: Since the question specifically asks for the poisonous gas produced during the burning of petrol in a car, the answer is carbon monoxide (CO).

### Final Answer:
The poisonous gas that comes out with petrol burning in a car is carbon monoxide (CO).