Pumice stone is an example of -
- gel
- solid sol
- foam
- sol
Answer
(2) solid sol
Solution
Pumice stone is a colloid of a gas (dispersed phase) in a solid (dispersion medium).
In the NCERT table of colloidal systems, gas in solid is named solid sol, with pumice stone and foam rubber as examples.
(Foam = gas in liquid, gel = liquid in solid, sol = solid in liquid.)
Answer: (2)