Question

A mixture of boron trichloride and hydrogen is subjected to silent electric discharge to form 'A' and \[{\text{HCl}}\] .' A' is mixed with \[{\text{N}}{{\text{H}}_{\text{3}}}\] and heated to \[200^\circ {\text{C}}\] to form 'B’. The formula of 'B' is:
A. \[{{\text{H}}_{\text{3}}}{\text{B}}{{\text{O}}_3}\]
B. \[{{\text{B}}_{\text{2}}}{{\text{O}}_3}\]
C. \[{{\text{B}}_{\text{2}}}{{\text{H}}_6}\]
D. \[{{\text{B}}_{\text{3}}}{{\text{N}}_3}{{\text{H}}_6}\]

Answer 1

Hint:In the first reaction, you can replace all boron-chlorine bonds with boron-hydrogen bonds. In the second reaction, two reagent molecules will add to form a single product which has structure similar to benzene.

Complete answer:
A mixture of boron trichloride and hydrogen is subjected to silent electric discharge to form 'A' and \[{\text{HCl}}\] .
Write the balanced chemical equation for the above process as shown below:
\[
  {\text{2 BC}}{{\text{l}}_{\text{3}}}{\text{ + 3 }}{{\text{H}}_2}{\text{ }}\xrightarrow[{{\text{discharge}}}]{{{\text{electric}}}}{\text{ }}{{\text{B}}_2}{{\text{H}}_6}{\;\;\;\;\;\;\;\;\;\;\;\text{+6}\;\;\;\;\;\;\;\;\;\;\text{ HCl}} \\
  {\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\text{ Compound 'A' }}
 \]
In the above reaction all the boron-chlorine bonds are replaced with boron-hydrogen bonds. New hydrogen-chlorine bonds are formed.
Thus, the compound ‘A’ is diborane with chemical formula \[{{\text{B}}_2}{{\text{H}}_6}\] .
' A' is mixed with \[{\text{N}}{{\text{H}}_{\text{3}}}\] and heated to \[200^\circ {\text{C}}\] to form 'B’.
Write the balanced chemical equation for the above process as shown below:
\[
  {{\text{B}}_2}{{\text{H}}_6}{\text{ + 2 N}}{{\text{H}}_3}{\text{ }} \to {{\text{B}}_2}{{\text{H}}_6} \cdot {\text{N}}{{\text{H}}_3}{\text{ }}\xrightarrow{{{{200}^o}{\text{C}}}}{\text{ }}{{\text{B}}_3}{{\text{N}}_3}{{\text{H}}_6} \\ {\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\text{ Compound B}}
 \]
The compound ‘B’ is \[{{\text{B}}_{\text{3}}}{{\text{N}}_3}{{\text{H}}_6}\]

Hence, the correct option is the option D.

Note:
The chemical formula \[{{\text{B}}_{\text{3}}}{{\text{N}}_3}{{\text{H}}_6}\]represents the compound borazine which is commonly called inorganic benzene. It contains 12 sigma bonds and 3 pi bonds, similar to those present in benzene. Alternate three \[{\text{BH}}\] units and three \[{\text{NH}}\] units are present.