6. Titration Curves Strong Acid-Strong Base Titrations The equivalence point of the titration is the point at which exactly enough titrant has been added to react with all of the substance being titrated with no titrant left over. In other words, at the equivalence point, the number of moles of titrant added so far corresponds exactly to the number of moles of substance being titrated according to the reaction stoichiometry.
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8. Weak Base / Strong Acid 1. The weak-base solution has a lower initial pH. 2. The pH drops more rapidly at the start, but less rapidly near the equivalence point. 3. The pH at the equivalence point does not equal 7.00. POINT OF EMPHASIS : The equivalence point for a weak base-strong acid titration has a pH < 7.00.
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10. Primary Standards A primary standard is a reagent that is extremely pure, stable, has no waters of hydration, and has a high molecular weight. Some primary standards for titration of acids: sodium carbonate: mol wt. = 105.99 g/mol tris -(hydroxymethyl)aminomethane (TRIS or THAM): mol wt. = 121.14 g/mol Some primary standards for titration of bases: potassium hydrogen phthalate (KHP): mol wt. = 204.23 g/mol potassium hydrogen iodate: mol wt. = 389.92 g/mol Some primary standards for redox titrations: potassium dichromate mol wt. = 294.19 g/mol
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