Using chemical equations, show how the triprotic acid H3PO4 ionizes in water. Phases, such as (l) or (aq), are optional.
To show the ionization of the triprotic acid H3PO4 in water, let's break it down into three steps. Each step represents the ionization of one hydrogen ion (H+). Here's how it proceeds:
Step 1:
H3PO4 (aq) + H2O (l) → H3O+ (aq) + H2PO4- (aq)
In this step, one hydrogen ion (H+) from H3PO4 combines with a water molecule (H2O) to form a hydronium ion (H3O+) and a hydrogen phosphate ion (H2PO4-).
Step 2:
H2PO4- (aq) + H2O (l) → H3O+ (aq) + HPO4^2- (aq)
In this step, the second hydrogen ion (H+) from H2PO4- combines with a water molecule (H2O) to form another hydronium ion (H3O+) and a hydrogen phosphate ion (HPO4^2-).
Step 3:
HPO4^2- (aq) + H2O (l) → H3O+ (aq) + PO4^3- (aq)
In this final step, the last hydrogen ion (H+) from HPO4^2- combines with a water molecule (H2O) to form the last hydronium ion (H3O+) and a phosphate ion (PO4^3-).
So, overall, the ionization of H3PO4 in water can be represented by the three steps mentioned above.