Mixture of pure nitric acid and pure hydrochloric

[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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