Though, theoretically the adsorption & desorption isotherms is expected
to coincide but sometimes at least a part of the isotherms does not coincide
and this phenomenon is known as adsorption hysteresis. In such cases, the
desorption equilibrium pressure is __________ that obtained for adsorption.
(A) Lower than
(B) Higher than
(C) Same as
(D) Either same or higher than