Why does the oxygen atom in H3O+ have a positive formal charge?

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Discussion Overview

The discussion revolves around the formal charge of the oxygen atom in the hydronium ion (H3O+) and the implications of acid dissociation in water. Participants explore the concepts of formal charge, electronegativity, and the definitions of acids and bases within the context of acid-base chemistry.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants question why the oxygen atom in H3O+ has a formal charge of +1, suggesting it should have a negative charge due to its higher electronegativity compared to hydrogen.
  • Another participant asserts that acids do not dissociate into H3O+ and OH-, challenging the premise of the original question and stating that the formal charge of oxygen in H3O+ is not +1.
  • A participant clarifies their inquiry about acid dissociation, specifically asking why an acid cannot accept a proton, linking this to the definition of acids.
  • One participant references the Brønsted-Lowry theory, stating that a substance that accepts a proton is classified as a base.

Areas of Agreement / Disagreement

Participants express differing views on the formal charge of oxygen in H3O+ and the nature of acid dissociation, indicating that multiple competing perspectives remain unresolved.

Contextual Notes

There are limitations in the discussion regarding the definitions of acids and bases, as well as the assumptions underlying formal charge calculations. The mathematical steps leading to the formal charge of +1 for oxygen in H3O+ are not fully explored.

semc
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Acid dissociates in water to form H3O+ and OH- but the formal charge on the oxygen atom in H3O+ is +1. Shouldn't the oxygen atom have a negative formal charge since it is more electronegative than hydrogen atom?
 
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semc said:
Acid dissociates in water to form H3O+ and OH- but the formal charge on the oxygen atom in H3O+ is +1. Shouldn't the oxygen atom have a negative formal charge since it is more electronegative than hydrogen atom?

Acids don't dissociate into H3O+ and OH-, formal charge of oxygen in H3O+ is not +1 - so I have no idea what you are asking about.

-2 + 3*(+1) = +1
 
Last edited by a moderator:
I meant to ask the acid dissociation in water into H+ and A-. So I wanted to ask why this is so. Why can't the acid accept the proton. Is this just because of the definition of acid?
 
Last edited by a moderator:

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