The protective power of a lyophilic colloidal sol is expressed in terms of

Which one of the following is not represented by sols?

Given below are two statements ($S-I$ and $S-II$):
$S-I$: Scattering of light by dispersed particles of a colloidal system is known as the Tyndall effect.
$S-II$: The diameter of the dispersed particles should not be much smaller than the wavelength of the light used.
Choose the most appropriate answer from the options given below.

The purple of Cassius is due to the presence of $......$.

At isoelectric point:

Which of the following electrolytes is the most effective for the coagulation of ferric hydroxide sol?