Question

What happens when a freshly prepared precipitate of $Fe(OH{)}_3$ is shaken with a small amount of $FeC{l}_3$ solution?

Answer 1

When a freshly prepared precipitate of $Fe(OH{)}_3$ is shaken with a small amount of $FeC{l}_3$ solution, collodial dispersion of $Fe(OH{)}_3$ is formed. The process is called peptization. During peptization, a precipitate is converted into colloidal particles by adding suitable electrolyte. In the above example, $FeC{l}_3$ solution is peptizing agent.