Acids and Bases

[josephcollins]

Hi People,
Could someone please give me a hand with this question : Explain why a mixture of pure nitric acid and pure hydrochloric (VII) acid (HClO4) contains H2NO3(+) ions and ClO4(-) ions.

Thanks a lot,
Joe

[movies]

HClO4 is a stronger acid than HNO3. The oxygens on the HNO3 are slightly basic, so they get protonated by the HClO4 to give the observed species.

[chem_tr]

Movies is right. There is always a stronger acid than a weaker one, so the weaker one can behave a base towards the strong acid.

You may wonder why the oxygens on HNO3 is more basic than that of HClO4. It is likely that chlorine has greater electronegativity than nitrogen, so the electronegativity totals are greater in HNO3. This may be the cause.

Regards
chem_tr

[GCT]

Yes, think in terms of the stronger conjugate acid -base pair inclusive of the overall reaction.


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