Question

Some of the following are suspensions:
(I) Fog
(II) Air
(III) Blood
(IV)Paint
(V) Aerosol sprays
(VI) Pearl
True suspensions are:
(A) I, II, III
(B) III, IV, V
(C) I, III, V
(D) I, II, V

Answer 1

Hint: A suspension is a heterogeneous mixture, i.e., mixtures in which the solute and the solvent molecules are distinguishable, in which the solute molecules separate out of the solution sometime after their introduction.

Complete step by step solution:
In the suspensions, the solute and the solvent molecules do not dissolve instead they get suspended throughout the bulk of the solvent, left floating around freely in the medium. The solid is dispersed throughout the fluid by mechanical agitation using certain suspending agents. An example of a suspension would be sand in water. The suspended particles are visible under the microscope and they settle down after a certain amount of time.
Among the above given compounds, fog is an example of a suspension in which the water vapour molecules the solute in the air which is the solvent. Air is a suspension of different solid particles and gases. Blood is a suspension in which the cells are the solutes and the plasma is the solvent. Paint is a colloid as the particles present in it do not settle over time. Aerosol sprays are also a colloid. Pearl is a colloid, not a suspension.
Therefore the true suspensions are: Fog, air, and blood.
The correct answer is option A.

Note:
Among the colloids, there are sols which are the colloids of solid particles in liquid, there are emulsions which are the colloids of the liquids in liquid solvents, there are aerosols in which small liquid droplets are dispersed within the medium.