Number of acidic protons in H3PO3

H3PO3 is the chemical formula for phosphorous acid. It is a diprotic acid, meaning it can donate two protons (H+) in solution. Let's break down the structure of H3PO3 to determine the number of acidic protons.

Structure of H3PO3
- H3PO3 is composed of one phosphorus (P) atom bonded to three hydrogen (H) atoms and one oxygen (O) atom.
- The phosphorus atom is in the +3 oxidation state, while the oxygen atom is in the -2 oxidation state.
- The chemical formula suggests that the phosphorus atom is bonded to three hydroxyl groups (-OH) and one hydrogen atom.

Acidic Proton Definition
An acidic proton refers to a hydrogen atom that is attached to an atom that is highly electronegative. This makes the hydrogen atom more acidic and prone to dissociating as a proton (H+).

Identification of Acidic Protons
In H3PO3, the acidic protons are the hydrogen atoms attached to the oxygen atoms. Let's identify them:

1. The first hydrogen atom is bonded to one of the oxygen atoms and can dissociate as an acidic proton.
2. The second hydrogen atom is bonded to the other oxygen atom and can also dissociate as an acidic proton.

Conclusion
Therefore, H3PO3 has two acidic protons, as indicated in option 'C'.