Hair cream is an example of which of the following?

The qualitative sketches $I$,$II$,and $III$ given below show the variation of surface tension with molar concentration of three different aqueous solutions of $KCl$,$CH_3OH$,and $CH_3(CH_2)_{11}OSO_3^{-}Na^{+}$ at room temperature. The correct assignment of the sketches is

Purification of colloids is done by the process of

Butter is a colloid. It is formed when

The properties of a colloidal solution are primarily due to:

Identify the colloidal molecule containing a hydrophilic head and a hydrophobic tail.