Final answer:
Option 2 (H2SO4) is not a proton dissociation of a monoprotic acid; it is a diprotic acid that can dissociate in two steps, thereby releasing two protons. Option 2 is correct.
Step-by-step explanation:
The question asks which option is not a proton dissociation of a monoprotic acid. Monoprotic acids are acids that can donate only one proton (hydrogen ion) to a base during a chemical reaction. Examples of monoprotic acids include hydrochloric acid (HCl) and nitric acid (HNO3).
On the other hand, sulfuric acid (H2SO4) is an example of a diprotic acid, meaning it can lose two protons. Lastly, water (H2O) is not considered to be a classic acid in the Arrhenius sense, so it is not classified as monoprotic in this context.
The correct answer to the question is option 2) H2SO4, as it is a diprotic acid, not a monoprotic acid. It can dissociate in two steps, first to form HSO4- and then to form SO42-. Each step involves the loss of a proton, providing two proton dissociations in total, unlike monoprotic acids that only have one such dissociation.