Question

The main factor responsible for weak acidic nature of b-f bonds in bf3 is

Answer 1

In BF3 the boron atom accepts the lone pairs of flurine to form pπ-pπ back bonding. Hence it's louis acidic character get decreased.

Answer 2

Let's add options to the question.
a) Large electronegativity of F
b) Three centred two electron bonds in BF3
c) pπ-dπ back bonding
d) pπ-pπ back bonding


● Answer -
d) pπ-pπ back bonding

● Explanation -
- BF3 shows strong pπ-pπ back bonding.
- This double bond character explains electron deficiency in BF3.
- Therefore, BF3 is less likely to donate electrons and acts as weak lewis acid.



Hope this helps you...