Q. What is the difference between a non-ferric alum and a ferric alum?

Answer

As the name suggests ferric alum is an alum that contains iron. The composition of this alum consists of ammonium sulfate and ferric sulfate. The crystallization of the solution of this mixture of ammonium sulfate and ferric sulfate form what is known as the ferric alum. The non-ferric alum on the other hand consists of an alum that does not have any iron in its composition. Hence, the difference between the two is in the composition of the alum and the non-ferric one is pure ammonium sulfate. Also, the raw materials which are used for making them are different. For ferric alum, bauxite is used as the raw material, and for non-ferric alum, aluminum trihydrate is used as the raw material.