1.Chemical adsorption is strong, unlayered, directional and strong.
2.Chemisorption happens due to specific forces so, it is not reversible generally.
3.Physical adsorption is weak, multilayer, non-directional and non-specific.
4. Also, physisorption happens due to weak attraction forces like van,der Waals forces. Physisorption is the process whereby molecules stick to a surface with a relatively weak interaction, up to 100 times weaker than chemisorption. Chemisorption is the adsorption by chemical bonding. Whereas physisorption can usually be reversed by adding heat, chemisorption cannot.