Question

The gold numbers of $A,B,C$ and $D$ are $0.04,0.002,10$ and $25$ respectively. The protective powers of $A,B,C$ and $D$ are in the order

• A. $A>B>C>D$
• B. $B>A>C>D$
• C. $D>C>B>A$
• D. $C>A>B>D$

Answer 1

Answer: (B)

$B>A>C>D$

The gold numbers of A, B, C and D are 0.04,0.002,10 and 25 respectively. The protective powers of A, B, C and D are in the order $B>A>C>D$.

Higher is the gold number, lower is the protective power and vice versa.

Gold Number is the minimum amount of protective colloid in milligrams which prevents a color change from red to violet of 10ml gold sol by the addition of 1 ml of 10% NaCl solution.