The temperature, at which the vapour pressure of a liquid becomes equal to the atmospheric pressure is known as

Options

A. Freezing point
B. Boiling point
C. Absolute temperature
D. None of these

Answer

To solve the question, we need to understand the concept of vapor pressure and its relationship with atmospheric pressure.

### Step-by-Step Solution:

1. **Understanding Vapor Pressure**:
- Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid at a given temperature. It indicates how readily the molecules of a liquid can escape into the vapor phase.

**Hint**: Remember that vapor pressure increases with temperature.

2. **Identifying the Relationship with Atmospheric Pressure**:
- The boiling point of a liquid is defined as the temperature at which its vapor pressure equals the atmospheric pressure surrounding it. At this point, the liquid can transition into the gas phase.

**Hint**: Think about what happens to a liquid when it reaches its boiling point.

3. **Analyzing the Options**:
- **Freezing Point**: This is the temperature at which a liquid turns into a solid, which is not related to vapor pressure equaling atmospheric pressure.
- **Boiling Point**: This is the correct term for the temperature at which vapor pressure equals atmospheric pressure.
- **Absolute Temperature**: This refers to a temperature scale starting from absolute zero and is not specifically related to vapor pressure.
- **None of These**: This option is incorrect since we have identified the correct term.

4. **Conclusion**:
- Based on the definitions and the analysis of the options, the correct answer is that the temperature at which the vapor pressure of a liquid becomes equal to the atmospheric pressure is known as the **boiling point**.

### Final Answer:
The temperature, at which the vapor pressure of a liquid becomes equal to the atmospheric pressure, is known as the **boiling point**.