Peptising agent is added to convert precipitate into colloidal solution. Explain with an example.

What happens when a colloidal sol of Fe(OH)₃ and As₂S₃ are mixed?

What is the difference between a sol and a gel?

Why are lyophillic colloidal sols are more stable than lyophobic colloidal sol.

Addition of Alum purifies water. Why?

What are the factors which influence the adsorption of a gas on a solid?

What are enzymes? Write a brief note on the mechanism of enzyme catalysis.

What do you mean by activity and selectivity of catalyst?

Describe some feature of catalysis by Zeolites.