Direct Titrations of Derivatives Exhibiting a Basic Character

6 Direct Titrations of Derivatives Exhibiting a Basic Character 

Most of the time, derivatives exhibiting a basic character are titrated with hydrochloric or sulfuric acid solutions. 

The disodium phosphate Na2HP04 can be titrated with a hydrochloric solution with a mixed indicator. The mixed indicator is a mixture of bromocresol green (color-change interval 3.8 pH 5.4) and methyl red (color-change interval 4.2 pH 6.3)  

The amphoteric ion dihydrogen phosphate is formed. However, the neutralization of the latter is not complete  

As H2P04 is too weak a base to be titrated in water, only one equivalence point is detected with the mixed indicator. With the same indicator, borax can be titrated with hydrochloric acid. It gives orthoboric acid, H3BO3, according to the reaction 

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