Page 89 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

Summary

OH CO3 HCO3
-
2-
-
E.Pph.ph. (1 flask): all OH ½ CO3 No E.P.
2-
st
-
2-
E.PM.O. (2 flask): all OH all CO3 all HCO3
nd
-
-

 The determination of their mixtures depends on using “Double-indicators titration

or Two-indicators titration” in which a mixture of two acids or two bases is

determined by titration using 2 indicators. i.e. We make 2 titrations in 2 different flasks,

one using ph.ph. & the other using M.O., and from the observed end points the

concentrations of the mixture components can be calculated.

 The reaction between HCl & Na CO or between HCl & NaHCO is an example
2 3 3

of displacement (substitution) titration where HCl [strong acid] displaces

carbonic acid [very weak acid] in its salts.

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