Question

Boric acid ${H_3}B{O_3}$ is a
A) Monobasic and Lewis acid.
B) Monobasic and Bronsted acid.
C) Tribasic and Lewis acid.
D) Tribasic and Bronsted acid.

Answer 1

Hint: We know that an acid is a species which has the capacity of donating a proton that is hydrogen ion is called Bronsted-Lowry acid and according to Lewis theory Lewis acids are defined as the electron acceptor.

Complete step by step answer:
We know that the Protic acid is an acid which will undergo ionization and produce hydrogen ions. However, aprotic acids don't produce any hydrogen ions. Although Boric acid contains 3 \[OH\] groups yet it can act as acid instead of acid. This is often because boric acid doesn't act as a proton donor rather it accepts a pair of electrons from \[O{H^ - }\] ions. It doesn't donate \[{H^ + }\] rather it accepts an electron pair from the solutions or the donor i.e. \[O{H^ - }\].
It is a very weak acid and ionizes mainly as a monobasic acid and that too to a very limited extent. Hence, Ortho boric acid \[{H_3}B{O_3}\;\] is a monobasic and Lewis acid.
Therefore option A is correct.


Note:
We also remember that in boric acid, albeit all three Hydrogen is linked to oxygen but not all three Hydrogen are replaceable. Here, boron acts as a Lewis acid because it is an electron-deficient species.
Boric acid may be a monobasic weak acid it doesn't dissociate completely to offer Hydrogen ions Hence, the 'n' factor of boric acid is 1. In solution, particularly at concentrations above boric acid forms a spread of other cyclic compounds and linear polymers that have higher n factors. So even with the foremost common explanation, in most cases, the particular n factor is going to be a variety depending upon the varied compounds present and their relative concentrations.