Which one is an example of a gel?

If the molecular weight of a compound is increased,then the sensitivity is decreased in which of the following methods?

How many of the following statements are correct $:$
$(i)$ When freshly prepared precipitate are converted into colloidal solution then process is called peptization.
$(ii)$ Lyophilic sol are mostly of inorganic nature.
$(iii)$ Lyophilic sol are highly solvated as particles have great affinity for solvent.
$(iv)$ Lyophobic sols are reversible sols so special methods are required to prepare them.

Soap acts as a cleansing agent because ...

Choose the correct reason$(s)$ for the stability of the lyophobic colloidal particles.
$(A)$ Preferential adsorption of ions on their surface from the solution.
$(B)$ Preferential adsorption of solvent on their surface from the solution.
$(C)$ Attraction between different particles having opposite charges on their surface.
$(D)$ Potential difference between the fixed layer and the diffused layer of opposite charges around the colloidal particles.

Brownian motion arises due to ....