Which of the following acids is considered a weak acid?

Citric acid is classified as a weak acid because it does not completely dissociate in water. When citric acid is dissolved in solution, only a small fraction of its molecules ionize to produce hydrogen ions (H⁺), which is characteristic of weak acids. This incomplete dissociation results in a lower concentration of hydrogen ions compared to strong acids, which fully dissociate.

In contrast, sulfuric acid, hydrochloric acid, and nitric acid are all strong acids. These acids fully dissociate in water, meaning that they release all of their hydrogen ions into the solution, resulting in a strong acidic environment. The distinction between weak and strong acids is important in understanding their behavior in chemical reactions and their effects on pH.