The $Purple \ of \ Cassius$ is $......$.

The density of gold is $19 \ g/cm^3$. If $1.9 \times 10^{-4} \ g$ of gold is dispersed in one litre of water to give a sol having spherical gold particles of radius $10 \ nm$,then the number of gold particles per $mm^3$ of the sol will be

When a dilute $AgNO_3$ solution is mixed with excess of dilute $KI$,the colloidal solution formed is

Sodium stearate forms in water:

Jelly is a colloidal solution of

For micelle formation,which of the following statements are correct?
$A$. Micelle formation is an exothermic process.
$B$. Micelle formation is an endothermic process.
$C$. The entropy change is positive.
$D$. The entropy change is negative.