36. A reaction between ammonia and boron trifluoride is given below.

$:{\mathrm{NH}}_{3}+{\mathrm{BF}}_{3}\to {\mathrm{H}}_{3}\mathrm{N}:{\mathrm{BF}}_{3}$

Identigy the acid and base in the reaction. Which theory explains it? What is the hybridisation of B and N in the reactants?

Although BF3 does not have a proton but acts as Lewis acid as it is an electron deficient compound. It reacts with NH3 by accepting the lone pair of electrons from NH3 and complete its octet. The reaction can be represented by
${\mathrm{BF}}_{3}+:{\mathrm{NH}}_{3}\to {\mathrm{BF}}_{3}←{\mathrm{NH}}_{3}$
Lewis electronic theory of acids and bases can explain it. Boron in BF3 in sp2 hybridised where N in NH3 is sp3 hybridised.