Question

Sulphur sol contains:
A. Discrete S- atoms
B. Discrete S- molecules
C. Large aggregates of S- molecules
D. Water dispersed in solid sulphur

Answer 1

We first need to know what are sols and its properties. Mixtures can be classified on the basis of particle size into three different types: solutions, suspensions, and colloids. A true solution forms a homogeneous mixture, Suspension is completely a heterogeneous mixture and a Colloidal Solution is also heterogeneous but the solute particles are large in size. A sol is a type of colloid in which solid particles are suspended in a liquid medium.

Complete step by step answer:
We need to know that a sol is a type of colloid. Paints and cell fluids are examples of sols. Sulphur sols are highly dispersed sols which contain about $0.08\%$ of sulphur. They are prepared by reduction of sulphur dioxide by hydrogen sulphide gas. It can also be obtained by passing extremely heated sulphur vapour into water that is air free. Large aggregates of Sulphur will be formed as ${S_8}$ molecules.
Hence, we can conclude that sulphur sol contains large aggregates of S- molecules.

So, the correct answer is Option C.

Note: We must be noted that when the dispersion medium is water, the colloidal system is often referred to as a hydrocolloid. Also, Sulphur colloid is lyophobic in nature because it is unstable, irreversible and cannot be created by simply mixing the sulphur with the liquid medium. They are called lyophobic because they do not interact strongly with the liquid medium. Lyophobic sols get aggravated easily because these sols carry charged particles which stabilizes them. Adding a suitable electrolyte removes the charge and they tend to aggregate and form colloidal sols.