Question

Consider the following statements related to colloids.
(I) Lyophobic colloids are not formed by simple mixing of dispersed phase and dispersion medium.
(II) For emulsions, both the dispersed phase and the dispersion medium are liquid.
(III) Micelles are produced by dissolving a surfactant in any solvent at any temperature.
(IV) Tyndall effect can be observed from a colloidal solution with dispersed phase having the same refractive index as that of the dispersion medium.
The option with the correct set of statements is

• A. (I) and (II)
• B. (II) and (III)
• C. (III) and (IV)
• D. (II) and (IV)

Answer 1

Answer: (A)

(I) and (II)

Answer 2

The correct set of statements related to colloids is:
(I) Lyophobic colloids are not formed by simple mixing of dispersed phase and dispersion medium.
(III) Micelles are produced by dissolving a surfactant in any solvent at any temperature.
Therefore, the correct option is (A) (I) and (II).

Lyophobic colloids cannot be produced by merely combining the dispersed phase and dispersion medium through basic mixing. The formation of their colloidal solutions necessitates the utilization of distinct techniques. Emulsions represent colloidal systems comprising a liquid dispersed phase within a liquid dispersion medium. Micelle formation takes place when the temperature surpasses a specific threshold called the Kraft temperature (TK) and when the concentration surpasses a distinct threshold known as the critical micelle concentration (CMC). The Tyndall effect becomes noticeable when there is a substantial discrepancy in the refractive indices between the dispersed phase and the dispersion medium.