ANS:B - decreases.

The integral heat of adsorption refers to the total heat released or absorbed when a certain quantity of adsorbate is adsorbed onto the surface of the adsorbent. This quantity of heat is often expressed per unit mass of adsorbate. The relationship between the concentration of the adsorbate and the integral heat of adsorption depends on several factors, including the nature of the adsorbate and the adsorbent, as well as the conditions of the adsorption process. In general, the integral heat of adsorption may increase or decrease with an increase in the concentration of the adsorbate. This variation can occur due to several reasons:

1. Adsorbate-adsorbent interaction: If the adsorbate molecules interact more strongly with the adsorbent surface at higher concentrations, the integral heat of adsorption may increase. Conversely, if the interaction weakens at higher concentrations, the integral heat of adsorption may decrease.
2. Surface coverage: At higher concentrations of adsorbate, the surface coverage of the adsorbent may increase. This can lead to changes in the energy associated with adsorption, affecting the integral heat of adsorption.
3. Competitive adsorption: In some cases, the presence of higher concentrations of other species in the adsorbate stream may affect the adsorption behavior of the target species. This can result in changes in the integral heat of adsorption.

Therefore, the integral heat of adsorption may increase or decrease with increasing concentration of the adsorbate, depending on various factors. It is not possible to make a generalized statement without considering the specific characteristics of the adsorbate-adsorbent system and the conditions of the adsorption process.