Question

Lyophilic sols are also called reversible colloids because:

• A. they can be reformed by mixing residue (dispersed phase) in dispersion medium even after drying
• B. they can be easily precipitated from the colloidal system
• C. once formed, the dispersion medium and dispersed phase cannot be separated
• D. special reversible reactions are used to prepare them

Answer 1

Answer: (A)

they can be reformed by mixing residue (dispersed phase) in dispersion medium even after drying

• Colloidal sols directly formed by mixing substances like gum, gelatine, starch, rubber, etc., with a suitable liquid (the dispersion medium) are called lyophilic sols.
  
• An important characteristic of these sols is that if the dispersion medium is separated from the dispersed phase, the sol can be reconstituted by simply remixing with the dispersion medium. That is why these sols are also called reversible sols.