Alums are hydrated double sulphate salt of aluminum with the general formula X (Al2SO4)2. Alum generally refers to Potassium Alum with the formula K (Al2SO4)2. 12 H2O. Other alums are named after the...

Alums are hydrated double sulphate salt of aluminum with the general formula X (Al2SO4)2. Alum generally refers to Potassium Alum with the formula K (Al2SO4)2. 12 H2O. Other alums are named after the monovalent cation that is present in the compound such as the Sodium alum when sodium cation is present, Ammonium alum when ammonium ions are present, etc..