Subject: Inorganic Chemistry · Chapter: Main Group Elements · Topic: Main Group Elements – General · Exam: CSIR-NET 2012 · Marks: 2 · Difficulty: Medium
Boric acid is a weak acid in aqueous solution. But its acidity increases significantly in the presence of ethylene glycol, because
(b)$\mathrm{B(OH)_4^{-}}$ is consumed in forming a compound with ethylene glycol.
(c)ethylene glycol neutralizes $\mathrm{H^{+}}$ released by boric acid.
(d)Boric acid dissociates better in the mixed-solvent.
Answer
Answer (as printed): B
Explanation
$\mathrm{B(OH)_3} + \mathrm{OH^{-}} \rightleftharpoons [\mathrm{B(OH)_4}]^{-}$ (reversible reaction). In presence of ethylene glycol, $[\mathrm{B(OH)_4}]^{-}$ is consumed as shown below, and boric acid behaves as a strong acid.