Which one is more acidic: H3PO3 or H3PO4

[Haochen He 3L]

Hi! I am not sure how to determine and compare the acidic strength between H3PO3 and H3PO4.
Could someone explain it?

[Jordi M 2I]

I believe the stronger acid is H3PO4 since the resulting anion is more stable due to the xtra oxygen which increases electronegativity. PO4-3 also has resonance structures which delocalize its electrons to disperse the negative charge across the molecule.

[Siwa Hwang 3G]

H3PO4 is more acidic since it has a greater number of oxygen atoms bonded to the central atom.

[Laura 3l]

Hi! I am not sure how to determine and compare the acidic strength between H3PO3 and H3PO4.
Could someone explain it?

H3PO4 is more acidic since this compound has an extra O and resonance, therefore it is more stable meaning it is more acidic.

[DavidTabib 3H]

H3PO4 since the extra oxygen provides more electronegativity, which pulls the electrons even further away from the electron.

[805593945]

Actually, H3PO3 is more acidic when you actually compare the pKa1 for both. The pKa1 for H3PO3 is 1.3 whereas for H3PO4 is 2.1; a lower pKa means that it is more acidic. The same goes for the pKa2. I think the difference in dipole moment accounts for H3PO3 additional acidity.

"H3PO3 is diprotic not triprotic," - Wikipedia.

[apurva-3E]

H3PO4 more oxygens will stabalize the charge better on the resulting anion

[Jason Knight - 1F]

H3PO3 is more acidic than H3PO4. H3PO3 is the more polar compound, leaving the Hydrogen-Oxygen bond weaker and the Hydrogen proton easier to disassociate from the molecule.

[Keshav Patel 14B 2B]

Anytime you have hydrogens and oxygens and you are determining strength of acid, always look at the number of oxygen. When you have more oxygen it stabilizes the structure much better with more oxygen than less after losing a hydrogen.

[Nicole Bruno Dis 1B]

H3PO3 is more polar, so the bonds between hydrogen and oxygen will be weaker, making the hydrogen ions easier to remove. In this way, H3PO3 is more acidic than H3PO4.

[Allison Peng 1D]

For H3PO3, when you draw in the dipoles, doesn't the lone hydrogen (attached directly to P) have a partial positive charge and the rest of the oxygens have a partial negative? This would make it more polar than H3PO4 like the answer stated, but shouldn't OH only lose the Hydrogen atom more easily if it has a partial positive charge?

[Carlie_Dorostkar_1A]

To find the stronger acid, you want to know which has the more stable conjugate base. H3PO4 will have the more stable base because there are more highly electronegative oxygen atoms that will be able to delocalize the charge caused by the loss of the H+.

[Nishan Reddy 3K]

H3PO4 is the stronger acid because the extra oxygen increases the stability of the resulting anion by pulling electron density away from the bond with the third H+ more effectively. Thus, allowing the H3PO4 molecule to give up its proton more readily than H3PO4.

[105778693]

H3PO4 is more acidic. You can see that it has an additional O, meaning resonance, which results in the molecule being more stable making it more acidic.

[Kati Rady-Pentek 1E]

H3PO4 is more acidic because there is a greater number of oxygen atoms which stabilize through resonance structures.

[Kelly McFarlane]

H3PO4 is the more acidic molecule because it contains more oxygen atoms.

[sidneypalacios]

The more electronegative/more the electrons are pulled away from the H in a compound, the more easily the H can be ripped away/the more acidic it is. Therefore, H3PO4 is more acidic since there are more electronegative O's on the compound

[Chelsea Greene 1L]

H3PO4 is more acidic because it has more oxygens.