University Chemistry ›› 2017, Vol. 32 ›› Issue (5): 49-54.doi: 10.3866/PKU.DXHX201612006

• Chemistry Laboratory • Previous Articles     Next Articles

The Differences between the Synthesis of Aluminum Potassium Sulfate by Aluminum Foil Dissolved in KOH and in H2SO4

Min PENG*(),Jian-Xin SHI,Zhou WANG,Rong LAI,Lian-Yun LI,Sai-Li ZHENG,Liu-Ping CHEN   

  • Published:2017-05-08
  • Contact: Min PENG


The differences between the synthesis of aluminum potassium sulfate by aluminum foil dissolved in KOH and in H2SO4 were studied. Analysis of the material balance during the entire synthesis process by back titration of aluminum ion told us that the yield of aluminum potassium sulfate was very low due to Al (OH)3 precipitation produced by side reactions during the dissolution of aluminum foil in KOH. Stiring and lowering the KOH concentration could help to promote the yield with the H2SO4 method still showing a higher yield. Besides, the H2SO4 method was easier and more convenient. In summary, the H2SO4 method was recommended for students to carry out the synthesis of aluminum potassium sulfate.

Key words: Potassium hydroxide, Sulphuric acid, Aluminum potassium sulfate dodecahydrate