Question

Draw the structure of boric acid showing hydrogen bonding. Which species is present in water? What is the hybridisation of boron in this species?

Answer 1

Boron accepts electrons from hydroxyl ions of water since it has one empty $2p$ orbital.

$B(OH{)}_3+2H_{2}O\to [B(OH{)}_4{]}^{-}+H_3{O}^{+}$

$\left[B\right(OH{)}_4{]}^{-}$ species are present in wate

In $\left[B\right(OH{)}_4{]}^{-}$ boron forms 4 covalent or sigma bond with 4 OH group and thus B in $\left[B\right(OH{)}_4{]}^{-}$ is $s{p}^3$ hybridised and $\left[B\right(OH{)}_4{]}^{-}$ has tetrahedral structure.