Answer:
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.
For example:
![H_3BO_3(aq.)+HS^-(aq.)\rightarrow H_2BO_3^-(aq.)+H_2S(aq.)](https://img.qammunity.org/2020/formulas/chemistry/college/r2fabc8orlnhcr8b90v3jarsw14r1ujx8n.png)
Here,
is loosing a proton, thus it is considered as a bronsted acid and after losing a proton, it forms
which is a conjugate base.
And,
is gaining a proton, thus it is considered as a bronsted base and after gaining a proton, it forms
which is a conjugate acid.
The sequence of the acids and bases in the above equation are:
![Acid+Base\rightarrow Base+Acid](https://img.qammunity.org/2020/formulas/chemistry/college/l1b3y1nbcfzfmv39ghdsn4s5pvr4eg4end.png)