**Valency factor of H3PO4, H3PO3, H3PO2**

The valency factor of a compound refers to the number of electrons an atom can gain, lose, or share to form chemical bonds with other atoms. It is determined by the number of valence electrons an atom possesses. In the case of phosphorous compounds like H3PO4, H3PO3, and H3PO2, the valency factor of phosphorous determines the number of bonds it forms with hydrogen and oxygen atoms.

**1. H3PO4 (Phosphoric Acid):**
- In H3PO4, phosphorous (P) is in its highest oxidation state, +5.
- Phosphorous has 5 valence electrons, and it can form 5 bonds by either accepting or sharing electrons.
- Each hydrogen atom (H) can contribute 1 electron, and oxygen (O) can contribute 2 electrons.
- Therefore, the valency factor of phosphorous in H3PO4 is 5.

**2. H3PO3 (Phosphorous Acid):**
- In H3PO3, phosphorous (P) is in its intermediate oxidation state, +3.
- Phosphorous has 5 valence electrons, but in this compound, it only forms 3 bonds.
- Each hydrogen atom (H) can contribute 1 electron, and oxygen (O) can contribute 2 electrons.
- Therefore, the valency factor of phosphorous in H3PO3 is 3.

**3. H3PO2 (Hypophosphorous Acid):**
- In H3PO2, phosphorous (P) is in its lowest oxidation state, +1.
- Phosphorous has 5 valence electrons, but in this compound, it only forms 1 bond.
- Each hydrogen atom (H) can contribute 1 electron, and oxygen (O) can contribute 2 electrons.
- Therefore, the valency factor of phosphorous in H3PO2 is 1.

In summary, the valency factors of H3PO4, H3PO3, and H3PO2 are 5, 3, and 1 respectively. These valency factors determine the number of bonds formed by phosphorous with hydrogen and oxygen atoms in each compound. It is important to note that the valency factor can vary based on the oxidation state of the phosphorous atom in different compounds.

3,2,1