Into how many parts are colloidal sols divided according to the nature of interaction between the dispersed phase and the dispersion medium?

$Fe(OH)_3$ is a positively charged sol. For its precipitation, the best precipitating agent is:

In general,for soaps,the concentration of surfactant at $CMC$ is around $mol \ L^{-1}$.

Which of the following electrolytes has the maximum coagulating power?

Equal volumes of two $AgI$ sols are mixed together. The first sol is obtained by adding $AgNO_3$ to a slight excess of $KI$,and the second sol is obtained by adding $KI$ to a slight excess of $AgNO_3$. What happens when they are mixed?

Sodium lauryl sulphate is an example of: