Here is the first extra credit problem (for those who have successfully managed 
to register their email address).  Turn in an answer (hard copy, or email copy) 
by this Friday, May 23, to earn either one point extra credit (if you made a 
decent attempt at the problem) or two points (if you get the problem correct).


Phosphate is a triprotic acid with 3 pK's.  pK1=2.2, pK2=7.2, pK3=12.7.  In a 
solution of 0.1 M phosphate buffer at pH 7.0 (i.e. concentration of all 
protonated species is 0.1 M), what is the M of each of the individual species, 
i.e. what are the following concentrations:

[H3PO4], [H2PO4^-1], [HPO4^-2], and [PO4^-3] ?

Show your work.

Dr. Light