The Lewis acid character of boron tri halides follows the or... | Chemistry | SolveeIt

Question

The Lewis acid character of boron tri halides follows the order :

$BCl _3> BF _3> BBr _3> BI _3$

$BI _3> BBr _3> BCl _3> BF _3$

$BBr _3> BI _3> BCl _3> BF _3$

$BF _3> BCl _3> BBr _3> BI _3$

Answer

$BI _3> BBr _3> BCl _3> BF _3$

Explanation

Solution

Extent of back bonding, reduces down the group leading to more Lewis acidic strength
(2p−2p)BF3>(2p−3p)BCl3>(2p−4p)BBr3>(2p−5p)BI3 (extent of back bonding)
BF3<BCl3<BBr3<BI3 (lewis acidic nature)
So, the correct option is (B).

Chemistry Question on p -Block Elements

Solution