Types & Characteristics of Colloids

Colloids are classified based on the nature of the dispersion medium and dispersed phase into:

• True solution and suspension

• Lyophilic and Lyophobic sols

• Solid, liquid, gas

• Homogeneous and heterogeneous mixtures

Which of the following is a lyophilic sol?

• Gold sol

• Ferric hydroxide sol

• Starch sol

• Arsenic sulfide sol

Which of the following is a lyophobic sol?

• Gum sol

• Starch sol

• Gold sol

• Gelatin sol

Lyophilic sols are:

• Readily reversible

• Irreversible

• Unstable

• Precipitate easily

Lyophobic sols are stabilized mainly by:

• Strong attraction between dispersed phase and dispersion medium

• Solvent molecules strongly solvating the dispersed particles

• Electrical charges on particles

• Hydrogen bonding

The colloids having strong affinity between dispersed phase and dispersion medium are called:

• Lyophobic

• Lyophilic

• Multimolecular

• Associated

Examples of multimolecular colloids include:

• Starch and protein

• Gold and sulphur sols

• Soap and detergent micelles

• Gelatin and agar-agar

Bredig’s arc method is used to prepare:

• Gold sol

• Ferric hydroxide sol

• Starch sol

• Soap sol

Which method of preparation involves breaking down larger particles?

• Aggregation

• Dispersion

• Condensation

• Dialysis

Peptization refers to:

• Breaking large particles into smaller particles

• Conversion of precipitate into colloidal sol by adding electrolyte

• Removing impurities by dialysis

• Condensation of molecules