Question

When $BC{l_3}$ reacts with excess of ${H_2}O$ in the presence of NaOH. Then the formed product(s) is/are:
(this question has multiple correct options)
A.$Na[B{(OH)_4}]$
B.NaCl
C.HOCl
D.HCl

Answer 1

$BC{l_3}$ or boron trichloride is a colourless gas which generally exudes a pungent odour. The structure of boron trichloride can be understood as follows: born is the central atom in this compound. It is bonded by 3 chlorine atoms by 3 sigma bonds. Also, there are no lone pairs of electrons present on the central atom. From this we can determine that there are 6 electrons present in the valence shell of the boron atom. Thus, boron trichloride acts like a Lewis base.

Complete step by step answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
The reactivity of the $- OH$ group is higher than -Cl group. Hence, when water and NaOH react with boron trichloride, the -OH substituents from these compounds substitute the $- Cl$ group and form the ion ${[B{(OH)_4}]^ - }$ . This ion has a unit negative charge; hence it attaches itself to the unit positive sodium ion. This results in the formation of $Na[B{(OH)_4}]$ . Also, the chlorine atoms which were released from $BC{l_3}$ attach to the remaining sodium ion to form NaCl. Hence, the chemical equation for this reaction can be given as:
$2BC{l_3} + 3{H_2}O + 2NaOH \to Na[B{(OH)_4}] + NaCl$
Hence, when $BC{l_3}$ reacts with excess of ${H_2}O$ in the presence of NaOH, then the formed products are $Na[B{(OH)_4}]$ and NaCl

Hence, Options A and B are the correct options.

Note:
$BC{l_3}$ gas is very reactive and can be corrosive when brought in contact with metals. It is also toxic for tissue cells. When a human comes in contact with this gas, it usually causes irritation in the eyes as well as the mucous membranes.