H3PO4, also known as phosphoric acid, is classified as a weak acid. This classification is based on its behavior in aqueous solutions.
When H3PO4 is dissolved in water, it partially dissociates into H+ ions and H2PO4– ions. The dissociation is not complete, meaning that only a fraction of the H3PO4 molecules donate their protons (H+) to the water. This partial dissociation is a characteristic of weak acids.
In contrast, strong acids like HCl or H2SO4 completely dissociate in water, releasing all their H+ ions. Since H3PO4 does not fully dissociate, it is considered a weak acid.
Additionally, H3PO4 is not classified as a base because it does not accept protons (H+) in aqueous solutions. Instead, it donates protons, which is a defining characteristic of acids.
In summary, H3PO4 is a weak acid due to its partial dissociation in water and its ability to donate protons.