Question

Orthoboric acid behaves as a weak monobasic acid giving $H_3{O}^{+}$ and

• A. $H_{2}B{O}_2^{-}$
• B. $H_{2}B{O}_2^{+}$
• C. $\left[B\right(OH{)}_4{]}^{-}$
• D. $\left[B\right(OH{)}_4{]}^{+}$

Answer 1

The correct option is C $\left[B\right(OH{)}_4{]}^{-}$

Boric acid is not an Arrhenius acid, it actually behaves like a Lewis acid. It accepts the electron pair from the water molecule as shown below:
$H_{3}B{O}_3+H_{2}O\to \left[B\right(OH{)}_4{]}^{-}+H_3{O}^{+}$