Page 97 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

Determination of Boric Acid (H BO )
3 3
Boric acid is a very weak monoprotic acid (pK = 9.2) so it can not be directly
a
titrated against a standard alkali.

- +
H BO BO + H + H O
3 3 2 2
metaborate ion

But if a sufficient amount of glycerol, mannitol or similar organic polyhydroxy

compound is added to boric acid, it will be converted into a relatively stronger
monoprotic acid that can be directly titrated against standard NaOH using ph.ph.

indicator.

A boric acid vaginal suppository is a

medication that helps promote a balance of

acid in your vagina. It can also treat vaginal
yeast infections by relieving symptoms like

itching and burning.

Boric acid has mild antibiotic properties

against fungal or bacterial infection. Boric acid ophthalmic (for the eyes) is used as
an eye wash to cleanse or irrigate the eyes

Boric acid can kill insects if they eat it. It disrupts their stomach and can affect their
nervous system.

(very weak acid) (relatively stronger acid)

Glyceroboric acid + NaOH → Sodium glyceroborate + H O
2

92