Question

Incorrect statement regarding X in the given reaction is: $B{F}_3+LiAl{H}_4\to \left(X\right)+LiF+Al{F}_3$

• A. 12 electrons are involved in bonding
• B. It has four (2 centre-2 electron) bonds
• C. It has two (three centre-two electron) bonds
• D. X does not react with ammonia

Answer 1

The correct option is D X does not react with ammonia

Boron trifluoride reacts with lithium aluminium hydride in diethyl ether to give diborane
$B{F}_3+LiAl{H}_4\to B_2{H}_6+3Li\left[Al{F}_4\right]$
Thus, the X is diborane $\left(B_2{H}_6\right)$
Diborane $\left(B_2{H}_6\right)$ has following structure,

It has two $3-\text{centred}-2e^{-}\text{bond and four}2\text{centred}-2e^{-}\text{bond}$
Total 12 electrons are involved in bonding.

Diborane react with $N{H}_3$ at different condition to gives various products like Boron nitride, Borazine and $\left[H_{2}B\right(N{H}_3{)}_2{]}^{+}\left[B{H}_4{]}^{-}\right(\text{ionic compound})$.
Thus, (d) is incorrect.