In the following question, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices:

Assertion: Langmuir adsorption is a single layer phenomenon .

Reason : It is due to van er Waals forces.

Assertion is true but the reason is false.

The variation of adsorption with pressure is known as an adsorption isotherm. It shows a correlation between pressure and the quantity of active surface sites involved in adsorption.
On the surface of the adsorbent, every empty space is the same size and form.
The greatest number of gaseous molecules that may be held at each site is one, and this process constantly releases heat energy.