Question

In the following reaction:

HCO₃^-(aq) + NH₃(aq) ↔ CO₃^2-(aq) + NH₄⁺(aq)

Select one:

a. NH₃ is an acid and HCO₃^2- is its conjugate base.

b. NH₃ is an acid and NH₄⁺ is its conjugate base.

c. HCO₃^- is an acid and CO₃^2- is its conjugate base.

d. NH₄⁺ is an acid and CO₃^2- is its conjugate base.

e. HCO₃^- is an acid and NH₃(aq) is its conjugate base.

Answer 1

Answer – We are given, reaction –

HCO3- (aq) + NH3(aq) <-----> CO32-(aq) + NH4+(aq)

Acid is the species that donate the proton or hydrogen ion (H+) in an aqueous solution. The base is the species that accept the hydrogen ion or proton.

When acid donates the proton and formed a negative charged ion called conjugate base of the acid. When base accepts the proton and formed positive ion species called conjugate acid of base.

In the above reaction HCO3- (aq) donate a proton and formed CO32-, hence HCO3- (aq) is acid. The NH3(aq) accepts the proton and formed NH4+(aq), hence NH3(aq) is base.

CO32-(aq) is the conjugate base of HCO3-(aq) and NH4+(aq) conjugate acid of NH3(aq).

HCO3- (aq) + NH3(aq) <-----> CO32-(aq)    +     NH4+(aq)

Acid              Base                Conjugate Base     Conjugate Acid

Thus, the option “c. HCO3- is acid and CO32- is its conjugate base” is the true statement.