Ionization Reactions of H2PO4-

What are the three reactions involving H2PO4-?

Explore the different reactions involving H2PO4- and how it behaves as a protic acid.


The three reactions involving H2PO4- are:

  1. H3PO4 (aq) + H2O(l) ⇒ H3O+ (aq) + H2PO4-(aq)
  2. H2PO4- (aq) + H2O(l) ⇒ H3O+ (aq) + HPO42- (aq)
  3. HPO42- (aq) + H2O(l) ⇒ H3O+ (aq) + PO43- (aq)
  4. In the given reactions, H2PO4- is involved in three ionization reactions, where it behaves as a protic acid, donating a proton to the water molecule. These reactions facilitate calculations for equilibrium concentrations in solutions involving H3PO4.

    The compound H2PO4- is engaging in three different reactions or dissociations. These reactions show how H2PO4- can act differently in various reactions:

    • First ionization: H3PO4 (aq) + H2O(l) ⇒ H3O+ (aq) + H2PO4-(aq)
    • Second ionization: H2PO4- (aq) + H2O(l) ⇒ H3O+ (aq) + HPO42- (aq)
    • Third ionization: HPO42- (aq) + H2O(l) ⇒ H3O+ (aq) + PO43- (aq)

    In each of these reactions, H2PO4- acts as a protic acid, donating a proton (H+) to the reaction medium, typically water. Understanding these individual reactions can make the calculation of equilibrium concentrations in a solution of H3PO4 less complicated.