H3PO4 has only one H atom?

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H3PO4 has only one H atom?

Postby Chem_Mod » Sun Aug 21, 2011 12:29 pm

Question: When determining the pH values of a buffer, how come the pH value listed for the compound H3PO4 is 12, but the species NaHPO4 added with Na3PO4 also have a pH of 12. Why do these species only have one H atom, instead of 3 in H3PO4.

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Re: H3PO4 has only one H atom?

Postby Chem_Mod » Sun Aug 21, 2011 12:29 pm

Answer: At pH 12 the solution is alkaline and the H3PO4 has already lost 2 or 3 H+ to form Na2HPO4 and Na3PO4. These are the species in solution at pH 12.


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