Aqueous solution of ortho-boric acid can be titrated against sodium hydroxide using phenolphthalein indicator only in presence of

Titration of aqueous solution of boric acid against NaOH is done using phenolphthalein in the presence of polyhydroxy compounds named as catechol and cis-glycerol. Boric acid forms a stable complexes with polyhydroxy compounds which helps in releasing H⁺ and H₃O⁺ in the solution This enhances the acidic strength of boric acid and then, it is titrated against NaOH.