Question

The protective power of the lyophilic colloids is expressed in terms of gold number, a term introduced by Zsigmondy. The gold number is the number of milligrams of the protective colloid that prevents the coagulation of $10mL$ of a red gold sol when $1mL$ of a $10$ percent solution of sodium chloride is added to it.

Which of the following statement(s) is/are correct

• A. Higher the gold number, more protective power of colloid
• B. Lower the gold number, more the protective power
• C. Higher the coagulation value, more the coagulation power
• D. Lower the coagulation value, higher the coagulation power

Answer 1

Answer: (B), (D)

The correct options are
B Lower the gold number, more the protective power
D Lower the coagulation value, higher the coagulation power

The gold number according to Zsigmondy may be defined as: "The number of milligrams of the protective colloid which must be added to 10 ccs 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, the higher the protective power of a colloid.
Also,
The reciprocal of coagulation value is regarded as the coagulating power or flocculating power. So, the lower the coagulation value, the higher the coagulation power.