An acid in terms of the Lowry-Brønsted theory is a substance that acts as a proton donor.

Here are the solutions to the chemistry questions.

7.1.1
An acid in terms of the Lowry-Brønsted theory is a substance that acts as a proton donor.

7.1.2
The substance that acts as an ampholyte in the above equations is $\text{HSO}_4^-$.
Reason: In reaction II, $\text{HSO}_4^-$ donates a proton to $\text{H}_2\text{O}$ to form $\text{SO}_4^{2-}$ and $\text{H}_3\text{O}^+$, thus acting as an acid. $\text{HSO}_4^-$ can also accept a proton (e.g., from a strong acid) to form $\text