Question

Which of the following statement(s) about $H_{3}B{O}_3$ is/are correct?

• A. It is a strong tribasic acid.
• B. It is prepared by acidifying an aqueous solution of borax.
• C. It has a layer structure in which planar $B{O}_3$ units are joined by hydrogen bonds.
• D. It does not act as proton donor as it acts as a Lewis acid by accepting lone pair of hydroxyl ions.

Answer 1

Answer: (B), (C), (D)

It has a layer structure in which planar $B{O}_3$ units are joined by hydrogen bonds.
It is prepared by acidifying an aqueous solution of borax.
It does not act as proton donor as it acts as a Lewis acid by accepting lone pair of hydroxyl ions.

Boric acid, also called hydrogen borate, boracic acid, orthoboric acid and acidium boricum , is a weak, monobasic lewis acid of boron by accepting lone pair often used as an anticeptic.
Boric acid may be prepared by reacting borax (sodium tetraborate decahydrate) with a acid such as HCl.
$N{a}_2{B}_4{O}_7.10H_{2}O+2HCl\to 4B\left(OH{)}_3\right[or{H}_{3}B{O}_3]+2NaCl+5H_{2}O$.
Crystalline boric acid consists of layers of $B{O}_3$ molecules held together by hydrogen bonds.
Hence options B,C & D are correct.