Answer:
H₂O and H₂CO₃
Step-by-step explanation:
Per the Brønsted-Lowry theory, an acid is a substance that can donate a proton to another substance.
![\text{HCO}_(3)^(-) + \underbrace{\hbox{H$_(2)$O }}_{\hbox{acid}} \, \rightleftharpoons \, \underbrace{\hbox{H$_(2)$CO$_(3)$}}_{\hbox{acid}} + \,\text{OH}^(-)](https://img.qammunity.org/2021/formulas/chemistry/high-school/jqu9zrj3ol5fmptw8qayiyehmo2l1qv8nq.png)
In the forward reaction, the water acts as a Brønsted-Lowry acid. It donates a proton to the bicarbonate ion and converts it to carbonic acid.
In the reverse reaction, the carbonic acid acts as a Brønsted-Lowry acid. It donates a proton to the hydroxide ion and converts it to water.