In shaving cream,the dispersion medium is

The size of colloidal particles is .....

In the preparation of ice cream,gelatin is often added as an ingredient for:

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

On adding $AgNO_3$ solution into $KI$ solution,a negatively charged colloidal sol is obtained when they are in:

Give information about the applications of colloids.