Diprotic Acid
An acid that can donate two protons per molecule.
Formula / equation
H₂A ⇌ 2H⁺ + A²⁻
Unit
mol/L
In depth
Diprotic acids require two moles of base per mole of acid for complete neutralisation and show two equivalence points on a titration curve, provided the two pKa values differ by at least three units. Their intermediate anion is amphiprotic.
Examples in the real world
Sulfuric acid, whose first proton is strong and second weak; carbonic and oxalic acids.