Question

Select the pair that consists of a base and its conjugate acid in that order. CO32−/CO22−

Answer 1

Answer: The pair that consists of a base and its conjugate acid in that order.$NH_3/NH_4^+$

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

$H_3PO_4\rightarrow H_PO_4{2^-}+2H^+$

$H_2CO_3\rightarrow HCO_3^-+H^+$

$NH_3+H^+\rightarrow NH_4^+$

$HCO_3^-\rightarrow CO_3^{2-}+H^+$

$NH_3$  is gaining a proton, thus it is considered as a brønsted-lowry base and after gaining a proton, it forms$NH_4^+$  which is a conjugate acid.