The example of a heteropolar sol is

The conditions given below are in the context of observing Tyndall effect in colloidal solutions:
$A$. The diameter of the colloidal particles is comparable to the wavelength of light used.
$B$. The diameter of the colloidal particles is much smaller than the wavelength of light used.
$C$. The diameter of the colloidal particles is much larger than the wavelength of light used.
$D$. The refractive indices of the dispersed phase and the dispersion medium are comparable.
$E$. The dispersed phase has a very different refractive index from the dispersion medium.
Choose the most appropriate conditions from the options given below:

$A$ coagulating agent frequently added to water to remove the suspended and colloidal impurities is

The number of colloidal systems from the following,which will have 'liquid' as the dispersion medium,is $.........$.
Gem stones,paints,smoke,cheese,milk,hair cream,insecticide sprays,froth,soap lather.

Which of the following is a hydrophilic colloidal sol?

The white of an egg is partly coagulated by heating,which can be converted back into a colloidal sol by adding some pepsin and a little $HCl$. This process is called: