(a) In physisorption adsorbate and adsorbent are held by weak vander Waal’* forces which break easily on increasing the temperature.
(b) Alum’* fine particles load themselves on the suspended particles to speed up the sedimentation and allowing the suspended particles to flocculate and settle down which can be removed.
(c) Brownian movement is caused by the unbalanced bombardment of the colloidal particles of the molecules of the dispersion medium. It has a stirring effect and helps in providing stability to colloidal solutions by not allowing them to settle down.
