Explain how water behaves in this reaction. Which definition of acids and bases would you apply?

Answer:

Water behaves as a base in this reaction. The Brønsted-Lowry definition should be applied because the reaction involves the transfer of a proton (H+) from carbonic acid (H2CO3) to water (H2O). Since a Brønsted-Lowry base is defined as a proton acceptor and water gains a proton to form H3O+, it acts as a base.