Prepare crystals of alum.

A cupful of water taken in beaker and a few drops of dilute sulphuric acid are added into it. The water is heated. When it starts boiling alum powder is added slowly while stirring continuously. Alum powder is added continuously till no more powder can be dissolved. The solution is filtered and allowed to cool down. Crystals of alum slowly form at the bottom of the beaker.

Crystals of Alum