Boron trifluoride on reaction with lithium al | vedclass

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Question

(A) The reaction of $BF_3$ with $LiAlH_4$ in ether produces diborane $(B_2H_6)$ as $X$: $4BF_3 + 3LiAlH_4 \rightarrow 2B_2H_6 + 3LiF + 3AlF_3$. $X$ $(

Vedclass · Accepted Answer

$15$

Vedclass · Answer

(A) The reaction of $BF_3$ with $LiAlH_4$ in ether produces diborane $(B_2H_6)$ as $X$: $4BF_3 + 3LiAlH_4 \rightarrow 2B_2H_6 + 3LiF + 3AlF_3$. $X$ $(B_2H_6)$ reacts with $NH_3$ to form an adduct, which on heating gives inorganic benzene (borazine, $B_3N_3H_6$) as $Z$: $3B_2H_6 + 6NH_3$ $\rightarrow 3[BH_2(NH_3)_2]^+[BH_4]^-$ $\xrightarrow{\Delta} 2B_3N_3H_6 + 12H_2$. Borazine $(B_3N_3H_6)$ has a cyclic structure similar to benzene. It contains $12$ $\sigma$-bonds ($6$ $B-N$ and $6$ $B-H/N-H$ bonds) and $3$ $\pi$-bonds. Thus, $x = 12$ and $y = 3$. $(x + y) = 12 + 3 = 15$.

Column-$I$	Column-$II$
$A$. $Bi^{+3} \to (BiO)^{+}$	$P$. Heat
$B$. $[AlO_2]^{-} \to Al(OH)_3$	$Q$. Hydrolysis
$C$. $SiO_4^{-4} \to Si_2O_7^{-6}$	$R$. Acidification
$D$. $(B_4O_7)^{-2} \to [B(OH)_3]$	$S$. Dilution with water

Boron trifluoride on reaction with lithium aluminium hydride in ether gives $LiF$, $AlF_3$ and $X$. $X$ on reaction with $NH_3$ gives $Y$. $Y$ on further heating gives a compound $Z$. The number of $\sigma$-bonds and $\pi$-bonds in $Z$ are $x$ and $y$ respectively. $(x+y)$ is equal to

Similar Questions

The type of hybridisation of boron in diborane is

Three pairs of compounds are given below. Identify the compound in each pair which has the group $13$ element in a more stable oxidation state. Give reasons for your choice and state the nature of bonding. $(A)$ $TlCl_3, TlCl$ $(B)$ $AlCl_3, AlCl$ $(C)$ $InCl_3, InCl$

Which one of the following statements is not correct?

Match Column-$I$ with Column-$II$ :

Column-$I$ Column-$II$

$A$. $Bi^{+3} \to (BiO)^{+}$ $P$. Heat

$B$. $[AlO_2]^{-} \to Al(OH)_3$ $Q$. Hydrolysis

$C$. $SiO_4^{-4} \to Si_2O_7^{-6}$ $R$. Acidification

$D$. $(B_4O_7)^{-2} \to [B(OH)_3]$ $S$. Dilution with water

Give reasons: Aluminium alloys are used to make aircraft bodies.

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