Colloidal solutions of gold prepared by different methods have different colours owing to [JIPMER 1999]

The fact that gold exhibits a variable valency of + 1 and + 3

The difference in the size of the colloidal particles

Different concentrations of gold

Presence of different types of foreign particles depending upon the method of preparation of the colloid

Colloidal solutions of gold prepared by different methods have differe

1.	Colloidal solutions of gold prepared by different methods have different colours owing to [JIPMER 1999]
A.	The difference in the size of the colloidal particles
B.	The fact that gold exhibits a variable valency of + 1 and + 3
C.	Different concentrations of gold
D.	Presence of different types of foreign particles depending upon the method of preparation of the colloid
Answer» B. The fact that gold exhibits a variable valency of + 1 and + 3