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 the dispersed phase cannot be separated.
D. Special reversible reactions are used to prepare them.

Answer 1

Hint- Colloidal sols are legitimately formed by blending substances like gum, gelatine, starch, elastic, and so on with a suitable liquid (the dispersion medium) are called lyophilic sols.

Complete answer:
Lyophobic sols are described by particles that are not unequivocally pulled into molecules of the dispersion medium and that are moderately effectively coagulated and precipitated. Lyophilic ("liquid-loving") sols are progressively stable and all the more intently look like true solutions. Numerous sols are moderate among lyophobic and lyophilic types.
Lyophilic colloids are liquid loving colloids (Lyo implies solvent and philic implies loving). At the point when these colloids are blended in with the suitable liquid, high power of attraction exists between colloidal particles and liquid. This outcome is an arrangement of an entirely stable solution called lyophilic sol. These sols are framed by substances like gums, starch and proteins. Lyophilic sol can be effortlessly arranged by legitimately blending colloid in with the liquid.
A significant quality of these sols is that if the dispersion medium is isolated from the scattered stage, the sol can be reconstituted by basically remixing with the dispersion medium. That is the reason these sols are likewise called reversible sols.

Hence, we can say that option A is the correct option.

Note: Sol, in physical science, a colloid (total of fine particles scattered in a continuous medium) in which the particles are solid and the dispersion medium is fluid. On the off chance that the dispersion medium is water, the colloid might be known as a hydrosol; and if air, an aerosol.