The vapour pressure of water depends upon _______

Options

A. Temperature
B. Volume of container
C. Surface area of container
D. All of these

Answer

To solve the question regarding what the vapor pressure of water depends upon, we can analyze the options provided step by step.

### Step 1: Understanding Vapor Pressure
Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid form. It is an important property of liquids, including water.

### Step 2: Analyzing the Options
The question provides four options:
1. Temperature
2. Volume of container
3. Surface area
4. All of these

### Step 3: Evaluating Each Option
- **Temperature**: The vapor pressure of water is known to depend significantly on temperature. As the temperature increases, the kinetic energy of water molecules increases, leading to more molecules escaping into the vapor phase, thus increasing the vapor pressure.

- **Volume of Container**: The volume of the container does not affect the vapor pressure of water. Vapor pressure is a property of the liquid itself and is independent of the amount of liquid or the volume of the container in which it is placed.

- **Surface Area**: Similarly, the surface area of the liquid does not affect the vapor pressure. While a larger surface area may allow more molecules to escape into the vapor phase, the equilibrium vapor pressure remains the same for a given temperature.

- **All of These**: Since we have established that vapor pressure does not depend on volume or surface area, this option is incorrect.

### Step 4: Conclusion
From the analysis above, we conclude that the vapor pressure of water depends only on temperature. Therefore, the correct answer is:

**Answer: Temperature**