Analytical Chem istry - DePauw University

62 Analytical Chemistry 2.0Practice Exercise 3.2(a) A negative value for K Ag,Hg means that the presence of Hg 2+ decreasesthe signal from Ag + .(b) In this case we need to consider an error of –1%, since the effect of Hg 2+is to decrease the signal from Ag + . To achieve this error, the term K × CA,I Iin equation 3.8 must be less than -1% of C A ; thusK × C =− 001 . × CAg,Hg Hg AgSubstituting in known values for K Ag,Hg and C Ag , we find that the maximumconcentration of Hg 2+ is 1.0 × 10 -8 M.Click here to return to the chapter.