what is meant by multi-layered in physical adsorption and single layered in chemical absorption

Thisis because phyisioadsorbtion is froum from vander waals force where as the chemical adsorption is form by chemical bonding.
physisorption forms multimolecular layer because the gas can be adsorbed one over the other by the vander waals forces, and they are (multimolecular layers) are formed under high pressure whereas in chemisorption is unimolecular because the chemical bond can be formed only with the layer of molecules coming in direct contact with the surface of the adsorbent hence chemisorption. is unimolecular

 

Regards

Arun