Question

Which is the correct order of decreasing acidity of lewis acids? *

(a) BBr3 > BCl3 > BF3
(b) BF3 > BCl3 > BBr3
(c) BCl3 > BF3 > BBr3
(d) BBr3 > BF3 > BCl3

Answer 1

The correct order of decreasing acidity of Lewis acids is (a) BBr₃ > BCl₃ > BF₃.

• A Lewis acid is an acidic compound that can act as an electron acceptor.
• The halides of Boron can accept electrons and thus all are Lewis acids.
• The strength of these acids depends on the availability of empty orbitals that can accommodate the accepted pair of electrons.
• Vacant d-orbitals are most readily available in Bromine followed by Chlorine and Fluorine.

Answer 2

Answer:

The correct order of decreasing acidity of Lewis acids is option (A). BBr₃ > BCl₃ > BF₃

Explanation:

1).Lewis acid are that acids which contains an empty orbital which is  capable of accepting an electron pair.

2). Lewis acids are boron trihalides but has some exception.

3). The acidity of this acids depends on accessibility of vacant orbitals  that can accept pair of electrons.

4). The availability of this vacant orbitals is higher in bromine following chlorine and fluorine respectively.

Therefore, The decreasing acidity of this Boron trihalides is BBr₃ > BCl₃ > BF₃