Which one of the following sols acts as a lyophilic colloid?

In which of the following,the sol is not correctly matched with respect to its charge?
$I$. $Al_2O_3 \cdot xH_2O$ sol; $+ve$ sol
$II$. Starch sol; $+ve$ sol
$III$. $TiO_2$ sol; $-ve$ sol
$IV$. Methylene blue sol; $+ve$ sol
The correct answer is

Flocculation value of $BaCl_2$ is much less than that of $KCl$ for sol $A$ and flocculation value of $Na_2SO_4$ is much less than that of $NaBr$ for sol $B.$ The correct statement among the following is

The gold numbers of protective colloids $A, B, C,$ and $D$ are $0.50, 0.01, 0.10,$ and $0.005$ respectively. The correct order of their protective power is:

Which of the following nanomaterials has all three dimensions less than $100 \ nm$?

Which of the following nanomaterials has exactly one dimension $< 100 \text{ nm}$?