Identify the correct statements from the following: (i) A closed vessel containing $90 \% \mathrm{CO}_2$ and $10 \% \mathrm{O}_2$ is an aerosol. (ii) Milk is an emulsion. (iii) Smoke is an aerosol. (iv) Peptísation is a method of purification of colloidal solution. (v) Ultrafilteration is a method of purification of colloidal solution.

(ii) Milk emulsion is considered as a permanent emulsion of the butterfat in water and casein act as emulsifier in milk emulsion. (iii) Aerosol is a suspension fine solid particles or liquid droplet, in air or another gas. Smoke is an example of aerosol. (v) Ultrafiltration is membrane filtration process similar to reverse osmosis, using hydrostatic pressure to force water through a semipermeable membrane. It is used for purification of colloidal solution. Thus, option (c) is correct.