Hint: A colloid is a heterogeneous mixture and its particles are too small that it cannot be seen by naked eyes. The components of the colloidal solution are –
Dispersed phase – the solute like a component or the dispersed particles in the colloidal form is called the dispersed phase.
Dispersed medium –the component in which the dispersed phase is suspended is called the dispersing medium. For example when liquid mixes into a gas it forms aerosol and fog is the example of aerosol.
A] emulsion-curd:- emulsion is formed when liquid is mixed in liquid and the example is milk and face cream. So, this option is not correct.
B] foam – mist:- foam is formed when gas mixes into liquid and the example is shaving cream. so, this option is also incorrect.
C] aerosol – smoke:- it is formed when a solid is mixed into gas and the example is smoke. Hence, this option is correct.
D] solid sol- cake:- it is formed when solid is mixed in solid and the example is milky glass. hence this option is incorrect.
So our required Ans is C that is aerosol- smoke
PROPERTIES OF COLLOIDS
Colloids are big enough to scatter a beam of light passing through it and make the path visible.
They do not settle down when left undisturbed
Colloids are stable
They cannot be separated from the mixture by the process of filtration.