Vapour pressure of a liquid depends on

Options

A. Volume of container
B. Amount of liquid
C. Surface area of container
D. Temperature

Answer

### Step-by-Step Solution:

1. **Understanding Vapor Pressure**:
Vapor pressure is defined as the pressure exerted by the vapor of a liquid when it is in equilibrium with its liquid phase at a given temperature.

2. **Factors Affecting Vapor Pressure**:
The vapor pressure of a liquid primarily depends on temperature. As the temperature increases, the kinetic energy of the molecules increases, leading to more molecules escaping into the vapor phase, thus increasing the vapor pressure.

3. **Independence from Container Size**:
The vapor pressure of a liquid is independent of the volume of the container. Whether the container is large or small, the vapor pressure will remain the same at a constant temperature because it is a characteristic property of the liquid.

4. **Equilibrium Constant**:
The vapor pressure can be considered an equilibrium constant for the phase transition between the liquid and vapor phases. This equilibrium constant is temperature-dependent, meaning it changes with temperature but remains constant at a specific temperature.

5. **Partial Pressure in Mixtures**:
In a mixture of two liquids (A and B), the total vapor pressure above the liquid mixture is the sum of the partial pressures of each component. The partial pressure of each component is directly proportional to its mole fraction in the vapor phase.

6. **Mathematical Representation**:
For components A and B, the total vapor pressure (P_total) can be expressed as:
\[ P_{total} = P_A + P_B \]
where \(P_A\) and \(P_B\) are the partial pressures of A and B, respectively.

7. **Using Raoult's Law**:
According to Raoult's Law, the partial pressure of each component in the vapor phase can be expressed as:
\[ P_A = P_{0A} \cdot x_A \]
\[ P_B = P_{0B} \cdot x_B \]
where \(P_{0A}\) and \(P_{0B}\) are the vapor pressures of pure components A and B at the same temperature, and \(x_A\) and \(x_B\) are their respective mole fractions in the liquid phase.