Acidic site
The proton is transferred from oxygen.
Deprotonation gives nitrate; nitrogen itself is not the proton donor.
Molecular compound · oxoacid
Nitric acid
HNO₃
Nitric acid is the molecular compound HNO₃. It contains one acidic O–H group attached to a nitrogen–oxygen framework. In dilute water, proton transfer to the solvent is essentially complete.
Identity versus solution: HNO₃ names the compound. Nitric-acid products are usually aqueous solutions whose concentration must be stated separately.
Essentials
The first structural fact is one acidic O–H group.
A condensed formula shows the proton-bearing oxygen before introducing detailed resonance bookkeeping.
Detail
Charge-separated Lewis notation is useful, but it is still a model.
Formal charges help satisfy electron-counting rules. They should not be read as a complete map of real electron density.
Nitrate
After deprotonation, resonance makes the three oxygen positions equivalent in the isolated nitrate ion.
No oxygen is permanently the unique “double-bond oxygen”.
Understand
In water, nitric acid behaves as a strong acid.
Proton transfer to water forms hydronium and nitrate. Strength describes extent of ionization, not concentration.
Strong ≠ concentrated
Strength and concentration are different properties.
A strong acid can be dilute; a weak acid can be concentrated.
Reference identifiers
Names and identifiers that pin down the chemical identity.
| Formula | HNO₃ |
|---|---|
| CAS Registry Number | 7697-37-2 |
| PubChem CID | 944 |
Advanced
Push past the first model without losing the simple picture.
Is nitrate one N=O plus two N–O bonds?
That is one Lewis contributor. The real nitrate ion is resonance-delocalized.
Does concentrated HNO₃ behave exactly like dilute HNO₃(aq)?
No. Solvation and speciation change with concentration.
Why can nitric acid oxidize other substances?
Nitrogen is in a high oxidation state, so redox chemistry can accompany acid chemistry depending on conditions.
Constituent elements