Diprotic acid
（重定向自Diprotic）
![Sulfuric acid is a strong acid that is completely dissociated in aqueous solution in its first deprotonation process.[3][4]](/Images/godic/202501/09/Sulfuric_acid.svg2548.png")
![This is an ideal titration curve for alanine, a diprotic amino acid.[21] Point 2 is the first equivalent point where the amount of NaOH added equals the amount of alanine in the original solution.](/Images/godic/202501/09/Titration_alanine2548.jpg")
![Carbonated water(H2CO3 aqueous solution) is one of the main ingredients listed the ingredient sheet of a can of Coca-Cola.](/Images/godic/202501/09/Lata_Coca_Cola2549.JPG")
In chemistry, diprotic acid is a class of Arrhenius acids which are capable of donating two protons or hydrogen cations per molecule when dissociating in aqueous solutions. The most important chemical feature for a diprotic acid molecule is its ability to deprotonate two protons in two sequential steps during dissociation. Most diprotic acids are common acids which are used everyday in many different areas. Also, they exist everywhere in nature, such as in human bodies.