Question
$$B{\left( {OH} \right)_3} + NaOH \to NaB{O_2} + Na\left[ {B{{\left( {OH} \right)}_4}} \right] + {H_2}O$$
How can this reaction is made to proceed in forward direction ?
A.
addition of $$cis\,1,2{\text{ - }}diol$$
B.
addition of borax
C.
addition of trans $$1,2{\text{ - }}diol$$
D.
addition of $$N{a_2}HP{O_4}$$
Answer :
addition of $$cis\,1,2{\text{ - }}diol$$
Solution :
$${H_3}B{O_3}$$ acts as weak monobasic Lewis acid.
$$B{\left( {OH} \right)_3} + NaOH \to Na\left[ {B{{\left( {OH} \right)}_4}} \right]$$
On addition of $$cis{\text{ - }}1,2{\text{ - }}diol$$ in $${H_3}B{O_3}$$ solution, acidic strength of $${H_3}B{O_3}$$ increases due to chelation effect.