BF_3 does not have proton but still acts as an acid and reacts with NH_3 Why is it so ? What type of bond is formed between the two ?

BF_3 does not have proton but still acts as an acid and reacts with NH

1.	BF_3 does not have proton but still acts as an acid and reacts with NH_3 Why is it so ? What type of bond is formed between the two ?
Answer» Solution :`BF_3`is an electron DEFICIENT MOLECULE and so ACTS as Lewis acid. `ddotNH_3` has ONE lone pair which it can donate to `BF_3` and form a COORDINATE bond. So, `NH_3` acts as a Lewis base. Comment `H_3N: to BE_3`