Question
With the help of suitable diagram, describe the variation in (i) chemisorption (ii) physisorption with changes in temperature and pressure of adsorbed gas. How may these diagram be used to distinguish the two of adsorption?
Solution
Answer:
first increases and then decreases with increase in temperature it is chemical adsorption.
The initial unexpected increase in the extent of adsorption with temperature is due to the fact that the heat supplied acts as a activation energy required for chemical adsorption which is much more than that of physical adsorption.
If it decreases with increase in temperature, it is physical adsorption.
If increases with increase in pressure, it is physical adsorption. If it first increases and then becomes independent of pressure then it is chemical adsorption.
first increases and then decreases with increase in temperature it is chemical adsorption.
The initial unexpected increase in the extent of adsorption with temperature is due to the fact that the heat supplied acts as a activation energy required for chemical adsorption which is much more than that of physical adsorption.
If it decreases with increase in temperature, it is physical adsorption.
If increases with increase in pressure, it is physical adsorption. If it first increases and then becomes independent of pressure then it is chemical adsorption.
