What are the most favourble conditions to liquefy a gas ?

Options

A. High temperature and high pressure
B. Law temperature and high pressure
C. Low temperature and low pressure
D. High temperature and low pressure

Explanation

To determine the most favorable conditions to liquefy a gas, we need to consider the effects of temperature and pressure on gas behavior. Here's a step-by-step solution:

### Step 1: Understand the Nature of Gases
Gases consist of molecules that are in constant motion and have high kinetic energy. This kinetic energy allows them to overcome intermolecular forces, keeping them in a gaseous state.

**Hint:** Remember that the kinetic energy of gas molecules is directly related to temperature.

### Step 2: Analyze the Effect of Temperature
Lowering the temperature reduces the kinetic energy of gas molecules. As the temperature decreases, the molecules move slower, which allows intermolecular forces to become more significant. This can lead to the gas molecules coming closer together and eventually forming a liquid.

**Hint:** Think about how cooling a gas affects its molecular motion.

### Step 3: Analyze the Effect of Pressure
Increasing the pressure on a gas compresses the molecules closer together. This increase in pressure enhances the intermolecular forces of attraction between the molecules. When the molecules are forced closer together, it becomes easier for them to transition from a gaseous state to a liquid state.

**Hint:** Consider how compressing a gas changes the distance between its molecules.

### Step 4: Combine Temperature and Pressure Effects
To liquefy a gas, both low temperature and high pressure are necessary. Low temperatures slow down the molecules, while high pressure forces them closer together, facilitating the transition from gas to liquid.

**Hint:** Recall the conditions under which gases are typically liquefied in industrial processes.

### Final Answer
The most favorable conditions to liquefy a gas are **low temperature and high pressure**.