Purification of colloids is done by the process of

The disease kala azar is caused by

What is the decreasing order of coagulating power of ions for an arsenious sulphide sol based on their charge?

Explain the coagulation of lyophilic sols and the protection of colloids.

Gold number is a measure of

When freshly prepared $Fe(OH)_3$ precipitate is boiled in water in the presence of a few drops of dilute $HCl$,a colloidal sol of ferric hydroxide is formed. This process is known as .......