NH3 can react with BF3, forming NH3¾BF3. In this reaction, 1) NH3 acts as a Brønsted base, accepting a proton from the BF3 molecule. 2) NH3 acts as a Lewis base, donating a proton to the BF3 molecule 3) NH3 acts as a Brønsted acid, donating a proton to the BF3 molecule 4) BF3 molecule acts as a Lewis acid, accepting an electron pair from the NH3 molecule to form a coordinate covalent bond 5) BF3 molecule acts as a Lewis base, donating an electron pair to the NH3 molecule to form a coordinate covalent bond