Question

Gold number is the measure of protective power of a lyophobic colloid.

• A. True
• B. False

Answer 1

The correct option is B False

The power of the hydrophilic colloid to prevent the precipitation of a lyophobic colloid by addition of an electrolyte depends upon the nature of the substance. The protective character of various hydrophilic substances can be expressed quantitatively by gold number.

The gold number according to Zsigmondy may be defined as "The number of milligrams of the protective colloid which must be added to $10$ cc of a given gold sol so as to just prevent its precipitation by addition of $1$ cc of $10\%$ $NaCl$ solution.

Smaller the gold number, higher the protective power of a colloid.