Adsorption of a gas on a solid surface is a surface phenomenon where gas molecules accumulate on the surface of a solid material. The extent of adsorption depends on various factors, including temperature, pressure, and the nature of the gas and solid involved. In general, adsorption increases with increasing pressure and decreasing temperature.To understand the relationship between adsorption, temperature, and pressure, we can refer to the Langmuir adsorption isotherm and the Freundlich adsorption isotherm. The Langmuir isotherm assumes monolayer adsorption on a homogeneous surface, while the Freundlich isotherm is an empirical equation that describes adsorption on heterogeneous surfaces.Experimental evidence:Let's consider an adsorption study of nitrogen gas N2 on activated carbon at different temperatures and pressures.Materials and methods:1. Prepare a known mass of activated carbon and place it in a closed container.2. Introduce nitrogen gas into the container at a known pressure and temperature.3. Allow the system to reach equilibrium, where the rate of adsorption equals the rate of desorption.4. Measure the amount of nitrogen gas adsorbed on the activated carbon using a suitable method, such as volumetric or gravimetric analysis.5. Repeat the experiment at different temperatures and pressures.Results and discussion:1. Effect of pressure: As the pressure of nitrogen gas increases, the concentration of gas molecules near the solid surface also increases. This leads to a higher probability of gas molecules colliding with the solid surface and getting adsorbed. Therefore, the amount of nitrogen gas adsorbed on the activated carbon increases with increasing pressure. This observation is consistent with both the Langmuir and Freundlich isotherms.2. Effect of temperature: At lower temperatures, the kinetic energy of gas molecules is lower, which means they are more likely to be captured by the attractive forces on the solid surface. As the temperature increases, the kinetic energy of gas molecules also increases, making it more difficult for them to be adsorbed. Consequently, the amount of nitrogen gas adsorbed on the activated carbon decreases with increasing temperature. This observation is consistent with the Langmuir isotherm, which predicts an inverse relationship between adsorption and temperature.In conclusion, the adsorption of a gas on a solid surface, such as nitrogen gas on activated carbon, generally increases with increasing pressure and decreases with increasing temperature. These trends can be explained by the Langmuir and Freundlich adsorption isotherms and are supported by experimental evidence obtained from adsorption studies.