Pressure exerted by water vapour in moist gas is called __________ .

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Context**: The question asks for the term that describes the pressure exerted by water vapor in a moist gas. To answer this, we need to understand the concept of water vapor and its behavior in a gaseous state.

2. **Identifying Water Vapor**: When water is present in a container, and the temperature is above 0 degrees Celsius, some of the water molecules will escape into the air above the water surface, forming water vapor (H2O in gaseous form).

3. **Defining the Pressure**: The pressure that this water vapor exerts in the space above the water is what we are interested in. This pressure is not the total pressure of the gas but specifically the pressure due to the water vapor alone.

4. **Term for the Pressure**: The pressure exerted by the water vapor in a moist gas is called "aqueous tension."

5. **Defining Aqueous Tension**: Aqueous tension can be defined as the partial pressure of water vapor above the surface of the water in a closed system. It represents how much pressure the water vapor contributes to the total pressure in the system.

6. **Final Answer**: Therefore, the pressure exerted by water vapor in moist gas is called **aqueous tension**.

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