NEET levelSingle correct optionDifficulty 1 of 3sc168
The gold number of a protective colloid is the number of milligrams of it that just prevent the coagulation of 10 mL of a standard gold sol on adding 1 mL of 10% NaCl solution. A protective colloid with a smaller gold number is:
Aa stronger coagulating agent for the gold sol
Bequally protective, since gold number does not measure protection
Ca poorer protective colloid
Da better protective colloid
Answer: D
A small gold number means only a small mass of the colloid is needed to protect the sol. Hence the smaller the gold number, the greater the protective power.