HCO3- +NH4 +         <---------     
                                 ---------->

Complete the above and identify the bronsted acid,bronsted base, conjugate acid and conjugate base

HCO₃^- (aq) + NH₄⁺ (aq)

< ---->  H₂CO₃ (aq) + NH₃(aq)
HCO₃^- (aq) is the base and its conjugate acid is H₂CO₃ (aq)
NH₄⁺ (aq)  is the acid and its conjugate base is NH₃(aq)
NH⁺₄ can not act like a base because N is already with four bonds and not able to accept a proton.