Phosphoric acid (H3 PO4) is a triprotic acid, phosphorous acid (H3 PO3) is a diprotic acid, and

step 1 The acidic hydrogens in the oxy acids of phosphorus are all bonded to oxygen. The hydrogens bond

Phosphoric acid (H3 PO4) is a triprotic acid, phosphorous...

Phosphoric acid $\left(\mathrm{H}_{3} \mathrm{PO}_{4}\right)$ is a triprotic acid, phosphorous acid $\left(\mathrm{H}_{3} \mathrm{PO}_{3}\right)$ is a diprotic acid, and hypophosphorous acid $\left(\mathrm{H}_{3} \mathrm{PO}_{2}\right)$ is a monoprotic acid. Explain this phenomenon.

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Bronsted-Lowry Acid Concept

This concept defines acids as proton donors. The number of protons a molecule can donate (whether one, two, or three) determines if an acid is monoprotic, diprotic, or triprotic. This fundamental idea is important for understanding acid-base reactions and how acids behave in solution.

Molecular Structure and Acidic Protons

The ionizable protons in an acid are determined by its molecular structure, specifically by how hydrogen atoms are bonded within the molecule. In many acids, only the protons attached to highly electronegative atoms (such as oxygen) are acidic because the resulting anion is stabilized. Hydrogens directly bonded to other atoms, like phosphorus, tend to be less acidic or non-ionizable.

Oxoacid Structure

Oxoacids are compounds that contain a central atom bonded to oxygen atoms, some of which are also bonded to hydrogen. The presence of oxygen allows for resonance stabilization of the conjugate base after deprotonation. However, the number of oxygen atoms and their bonding patterns also dictate how many of the hydrogen atoms are actually acidic, explaining why similar molecular formulas can yield different numbers of ionizable protons.

Please give Ace some feedback