Question: Which of the following product(s) may be formed by the reaction of diborane with ammonia? (A) \( {...

Question

Which of the following product(s) may be formed by the reaction of diborane with ammonia?
(A) ${(BN)_x}$
(B) ${B_2}{H_6}.2N{H_3}$
(C) ${B_3}{N_3}{H_6}$
(D) ${B_2}{H_6}.N{H_3}$

Answer 1

Solution

As we know that diborane is a highly unstable gas at room temperature with a repulsively sweet odour, so when diborane reacts with ammonia at various temperatures then it will also give various products respectively.

Complete answer:
When we react to diborane with ammonia at different conditions or at different temperatures, then we also get different products at different temperatures, which are as follows:-
$*$ At low temperature (excess of $N{H_3}$ )-
${B_2}{H_6} + 2N{H_3} \to {B_2}{H_6}.2N{H_3}\;$
In the above reaction, when we react diborane with two moles of ammonia at a very low temperature and also excess of $N{H_3}$ then it will give inorganic benzene or ${B_2}{H_6}.2N{H_3}$ .
$*$ At high temperature (excess of $N{H_3}$ )-
${B_2}{H_6} + N{H_3} \to {(BN)_x} + {H_2}$
In the above reaction, when we react to diborane with one mole of ammonia at a high temperature and also excess of $N{H_3}$ then it will give ${(BN)_x}$ .
$*$ At extreme high temperature-
${B_2}{H_6} + N{H_3} \to {B_3}{N_3}{H_6}\;$
In the above reaction, when we react diborane with one mole of ammonia at extreme high temperature and there is no excess of ammonia, then it will give Borazine or ${B_3}{N_3}{H_6}$ .
Therefore, when we react diborane with ammonia at different conditions or at different temperature, then we also get different products at different temperature such that ${(BN)_x}$ , ${B_2}{H_6}.2N{H_3}$ and ${B_3}{N_3}{H_6}$ as well.
Hence, the correct options are (A) ${(BN)_x}$ , (B) ${B_2}{H_6}.2N{H_3}$ and (C) ${B_3}{N_3}{H_6}$ .

Note:
Diborane is a colourless, extremely combustible gas with an odour that is horrible and sickly sweet. It spontaneously ignites in damp air at room temperature at high concentrations. It produces hydrogen and boric acid when it combines with water. Because diborane vapours are heavier than air, they can accumulate in low-lying regions.