In the physical chemistry of surface chemistry, the adsorption of a gas on a solid surface is a complex process that depends on several factors, including temperature. The relationship between temperature and gas adsorption can be described using adsorption isotherms, such as the Langmuir and Freundlich isotherms, which provide a mathematical representation of the adsorption process.The effect of temperature on gas adsorption can be understood in terms of the adsorption enthalpy H_ads and the adsorption entropy S_ads . The Gibbs free energy change G_ads associated with the adsorption process is given by the equation:G_ads = H_ads - TS_adswhere T is the temperature in Kelvin.The sign of G_ads determines the spontaneity of the adsorption process. If G_ads is negative, the adsorption process is spontaneous, while if it is positive, the process is non-spontaneous.1. Physisorption: In physisorption, gas molecules are adsorbed on the solid surface through weak van der Waals forces. The adsorption enthalpy H_ads is typically low less than 40 kJ/mol . As the temperature increases, the kinetic energy of the gas molecules also increases, which can overcome the weak attractive forces between the gas molecules and the solid surface. Consequently, physisorption generally decreases with increasing temperature.2. Chemisorption: In chemisorption, gas molecules form chemical bonds with the solid surface, resulting in stronger interactions and higher adsorption enthalpy H_ads values greater than 40 kJ/mol . The effect of temperature on chemisorption is more complex and can be understood using the Arrhenius equation:k = Ae^-Ea/RT where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.In chemisorption, increasing the temperature can increase the rate of adsorption by providing the necessary energy to overcome the activation energy barrier Ea . However, at very high temperatures, the adsorbed molecules may gain enough energy to break the chemical bonds and desorb from the surface, leading to a decrease in adsorption.In summary, the adsorption of a gas on a solid surface is influenced by temperature, with physisorption generally decreasing with increasing temperature, while chemisorption can initially increase with temperature before decreasing at very high temperatures. The specific relationship between temperature and gas adsorption depends on the nature of the gas-solid interaction and the adsorption mechanism involved.