Taking advantage of this lack of electrons, polyhydroxy compounds (such as glycerol and glycerol) are added to form a stable complex to strengthen its acidity. The reason why boric acid is acidic: O. | b (OH) 3+2H2O = HO-B.
Extended data:
Boric acid is a very weak acid, and some textbooks and manuals mention that boric acid is a ternary acid with a third-order ionization constant. The pKa 1 of boric acid is 9.24, pka2 is 12.74 and pka3 is 13.4. Later, N.Ingri and others made an in-depth study on this issue in the 1960s, and studied the equilibrium of boric acid by potential method.
It is not confirmed that borate ions with average charge number less than-1 exist in the aqueous solution, that is, there are no high valence anions such as HBO3 2- or BO3 3- in the solution. After glycerol is added to boric acid, the acidity of boric acid will be enhanced. The formed borate ester burns to produce a green flame, which can be used to identify boron-containing compounds. The experimental method failed to prove that boric acid has a second-order and third-order dissociation equilibrium, so boric acid can only be considered as a monobasic acid.
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