Question

The gold numbers of protective colloids A,B,C and D are $0.02,0.002,5\text{and}30$ respectively, The protective powers of $A,B,C\text{and}D$ are in the order:

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

Answer 1

The correct option is D $B>A>C>D$

Given that,
Gold numbers of protective colloids are
$A=0.02$
$B=0.002$
$C=5$
$D=30$
We know,
Gold number of sol $\propto \frac{1}{\text{protective power of sol}}$
i.e., Smaller is the gold number of protective colloid greater is its protective power.
Thus, Gold no. in decreasing order $D>C>A>B$.
Hence, protective power is$B>A>C>D$.