Question

Which of the following is not the correct difference between lyophobic and lyophilic sols?
a.) (Lyophobic sols) Require special methods for preparation (Lyophilic sol) can be prepared by shaking with the solvent.
b.) (Lyophobic sols) Are reversible (Lyophilic sol) are irreversible.
c.) (Lyophobic sols) Easily coagulated by electrolytes (Lyophilic sol) cannot be easily coagulated.
d.) (Lyophobic sols) are less stable (Lyophilic sol) Are more stable.

Answer 1

Hint: ols are nothing but Colloidal solutions. They are heterogeneous in nature. The particles of a colloid are too small to be individually seen by the naked eyes. The size of colloidal particles lies between ${ 1nm }$ to ${ 1000 nm }$.

Complete step by step solution:
Lyophobic sols are prepared by indirect methods such as peptization hydrolysis, electro-dispersion, etc. while lyophilic sols are easily prepared by shaking dispersed phase with the dispersion medium.
Lyophobic sols are irreversible sols such as sulfur, gold sol, etc while lyophilic sols are reversible sols such as gums, starch, albumin, etc.
Lyophobic sols are easily coagulated while lyophilic sols are not coagulated easily.
Lyophobic sols are less stable as their stability is due to charge only whereas lyophilic sols are more stable as their stability is due to charge and solvation of the particles.

Hence, the correct option is B.

Additional Information:
Tyndall effect shows more scattering in lyophobic sol whereas it shows less scattering in lyophilic sol.
In lyophobic sol, the particles can be seen under the microscope while in lyophilic sol, the particles cannot be seen under a microscope.
Lyophobic sols are precipitated by a low concentration of electrolytes whereas lyophilic sols are precipitated by a high concentration of electrolytes.

Note: The possibility to make a mistake is that lyophobic sols are reversible while lyophilic sol is irreversible but lyophilic sols are reversible because on evaporating the liquid, the residue left will pass into a colloidal state in addition to a liquid.
Lyophobic: Irreversible, because on evaporating the liquid, the residue left cannot be converted into solution on the mere addition of liquid.