Question

Explain with suitable examples. (i) Alcosol (ii) Aerosol (iii) Hydrosol?

Answer 1

Depending upon whether the dispersing medium and dispersed phase are gas, liquid, or solid, eight types of colloidal systems are possible.

(i) Alcosol

• When the dispersed phase is solid, and the dispersion medium is alcohol, then the colloids formed are referred to as alcosol.
• An example of alcosol is the sol of cellulose nitrate in ethyl alcohol.

(ii) Aerosol

• When the dispersed phase is liquid or solid, and the dispersing medium is gas, then the colloids formed are referred to as aerosols.
• Fog and mist are examples of aerosols where the dispersed phase is liquid and the dispersing medium is gas.
• Smoke and automobile exhaust are examples of aerosols where the dispersed phase is solid and the dispersing medium is gas.

(iii) Hydrosol

• When the dispersed phase is solid, and the dispersion medium is water, then the colloids formed are referred to as hydrosol.
• Examples of hydrosols are gold sol and starch sol.