The correct order of Lewis acidity for BX_3 i | vedclass

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Question

(A) The Lewis acidity of boron trihalides $(BX_3)$ depends on the extent of $p\pi-p\pi$ back-bonding between the halogen atom and the boron atom. In $

Vedclass · Accepted Answer

$BF_3 < BCl_3 < BBr_3 < BI_3$

Vedclass · Answer

(A) The Lewis acidity of boron trihalides $(BX_3)$ depends on the extent of $p\pi-p\pi$ back-bonding between the halogen atom and the boron atom. In $BF_3$,the fluorine atom has a small size and its $2p$ orbitals effectively overlap with the empty $2p$ orbital of boron,leading to strong back-bonding. As the size of the halogen increases from $F$ to $I$,the effectiveness of $p\pi-p\pi$ back-bonding decreases $(F > Cl > Br > I)$. Since back-bonding reduces the electron deficiency of the boron atom,the Lewis acidity increases as the back-bonding decreases. Therefore,the correct order of Lewis acidity is $BF_3 < BCl_3 < BBr_3 < BI_3$.

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

The correct order of Lewis acidity for $BX_3$ is:

Similar Questions

Match the following:

Column $I$ Column $II$

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

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

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

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

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