An example of a micelle is ........

Consider the following statements:
Statement-$I$ : Gold sol is prepared by Bredig's arc method.
Statement-$II$ : Bredig's arc method involves both dispersion and condensation.

Identify the negatively charged sol from the following.

The surface tension of a soap solution is $30 \times 10^{-3} \, N/m$. The work done to increase the surface area of a soap film from $5 \, cm \times 5 \, cm$ to $10 \, cm \times 10 \, cm$ is:

Explain the coagulation of lyophilic sols and the protection of colloids.

The macromolecular colloids among the following are:
$I$. Starch solution
$II$. Sulphur sol
$III$. Synthetic detergent
$IV$. Synthetic rubber