Question

A mixture of sulphur and carbon disulphide is:
(A) Heterogeneous and shows Tyndall effect
(B) Homogeneous and shows Tyndall effect
(C) Heterogeneous and does not show Tyndall effect
(D) Homogeneous and does not show Tyndall effect

Answer 1

Hint: A mixture of sulphur and carbon disulphide is colloidal in nature. In a colloidal solution, the particles are bigger than those in solutions. So they scatter light easily in a normal trajectory and do not pass through any mixture. This light scattering phenomenon is the reason for blue coloured eyeballs in humans.

Complete step by step answer:
- A mixture of sulphur and carbon disulphide is an example of colloid. It does not form a uniform composition. So, the properties of the mixture are different throughout the solution. Hence, it will form a heterogeneous colloid.
- It shows the Tyndall effect. The reason behind this is that sulphur remains suspended in water but settles down as a bottom layer in carbon disulphide. So, suspended particles can show this Tyndall effect.
- The Tyndall effect is the special phenomenon where the light scatters as a beam through a colloid or suspension. The individual particles of a colloid, when kept in front of a light source, do not allow the source of light to completely pass through it.

- There are two mandatory conditions of Tyndall effect. They are listed below.
1) The diameter of the colloidal particles should be smaller than the wavelength of the light used.
2) There should be a considerable difference between the refractive index of the dispersion medium and the dispersed phase.
Thus, we can conclude that a mixture of sulphur and carbon dioxide is heterogeneous and can show Tyndall effect. So, the correct answer is “Option A”.

Note: Colloidal solutions appear as homogeneous but they are actually heterogeneous. A colloid is a mixture in which one substance is dispersed through another substance. A common example of colloid is milk.