which of the following factors affects the adsorption of a gas on solid ?

Options

A. Critical temperture `(t_(c))`
B. temperature of gas
C. pressure of gas
D. All of these

Answer

To determine which factors affect the adsorption of a gas on a solid, let's analyze each option provided in the question step by step.

### Step 1: Understanding Critical Temperature
- **Definition**: The critical temperature is the temperature above which a gas cannot be liquefied, regardless of the pressure applied.
- **Effect on Adsorption**: The extent of adsorption is directly proportional to the critical temperature. Higher critical temperatures generally indicate that a gas can be more easily adsorbed onto a solid.

### Step 2: Analyzing Temperature of the Gas
- **Effect on Adsorption**: The temperature of the gas is inversely proportional to adsorption. As the temperature increases, the kinetic energy of gas molecules also increases, which can lead to a greater tendency for the molecules to escape from the surface of the solid (desorption). Therefore, higher temperatures typically result in lower adsorption.

### Step 3: Evaluating Pressure of the Gas
- **Effect on Adsorption**: The pressure of the gas is directly proportional to adsorption. As pressure increases, more gas molecules are available to interact with the solid surface, leading to an increase in the amount of gas adsorbed.

### Step 4: Conclusion
- After analyzing all three factors:
- Critical temperature affects adsorption positively.
- Temperature of the gas affects adsorption negatively.
- Pressure of the gas affects adsorption positively.

Thus, all these factors—critical temperature, temperature of the gas, and pressure of the gas—affect the adsorption of a gas on a solid.

### Final Answer
The correct choice is **4. All of these**.

---