Question

Gold number is associated with:
a.) Electrophoresis
b.) Purple of cassius
c.) Protective colloid
d.) Amount of pure gold

Answer 1

Hint: The term gold number is related to the colloidal sols. It is a kind of protective power of colloids. The colloidal sols are of two types i.e. lyophobic sol and lyophilic sol. Electrophoresis is a separation process used to separate the electrical charges.

Complete step by step answer:
Firstly, let us define the gold number. Gold number is a minimum weight measured in milligrams to avoid the coagulation of 10 ml of a standard gold sol, on coagulation colour changes from red to blue.
Now, if we see the options, the first option is electrophoresis, it is a kinetic process which separates the charged particles especially in the protein molecules.
The second is purple of cassius is a purple coloured pigment formed by the reaction of gold salts with tin (II) chloride, and used for the testing of gold.
Talking about the third option, lyophilic colloid is known to be the protective colloid. In the lyophobic sol, to avoid the precipitation, electrolytes are added. Gold number is the protective power of the lyophilic colloid.
Now the fourth option is the amount of pure gold, i.e. 24 carat gold.
So, we can conclude that the gold number is associated with the protective colloid. The correct option is C.

Note: Don’t get confused between the gold number and the amount of pure gold. Lyophilic colloid and lyophobic colloid are two different types. Lyophilic colloids are more stable in solvent.