Titration Study on Strengthening the Boric Acid of Weak Acid

Boric acid is a weak polyacid,it can not direct titration with sodium hydroxide standard solution.In the effect of mannitol and glycerol,Boric acid can quantitativeform a complex acid and its pH is lower.The complex acid can direct titration with Sodium hydroxide.In this paper,though lowest pH value method and the maximum consumption of alkali method,we found that the strengthening effect of mannitol is better than that of glycerol.It can achieve accurate titration of 0.10mol/L solution.At the conditioning of n(C6H14O6)∶n(H3BO3)=4∶1 with mannitol,Boric acid of different concentrations has little differences with the strengthening effect ofmannitol.It achieved satisfactory result with appication of the research in mixed acid titration.