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Titration

emily-ramsey
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Titration

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  1. TitrationThe word “titration” comes from the Latin word titalus, meaning inscription or title. The French word titre also from this origin, means rank. Titration, by definition, is the determination of rank or concentration of a solution with respect to water with a pH of 7 (which is the pH of pure water). The origins of volumetric analysis are in late 18th century French chemistry.Francois Antoine Henri – first buretteJoseph Louis Gay-Lussac – indigo solution and improved burette Karl Fiedrich Mohr- redesigned burette OLD GUYS:

  2. Titration The controlled addition of the measured amount of a solution of known concentration required to react completely with a measured amount of a solution of unknown concentration.

  3. Titration Setup • Common in the laboratory as a method of quantitative analysis that can be used to determine the concentration of a known reactant. The titrant drops from the burette into the analyte solution in the flask. An indicator present then changes color permanently at the endpoint. • Titrant = a reagent of a known concentration and volume used to react with a solution of the analyte, whose concentration is not known in advance. • Endpoint = the point at which the titration is complete, as determined by an indicator.

  4. Equivalence Point • The point in acid-base titrations in which equivalent quantities of acidic cations and basic anions are present. • Indications of reaching equivalence point • Precipitate formation • Color change • pH change • Temperature changes

  5. Indicators -Substances that change in color on the passage from acidity to alkalinityor the vice-versa. • pH paper • Litmus paper • Universal indicator • Phenolphthalein • Cabbage juice

  6. Preparing a sample for Titration • Titrant and analyte are required to be aqueous, or in solution form. If the sample is not a liquid or solution, the samples must be dissolved. If the analyte is very concentrated in the sample, it’s useful to dilute the sample. • By controlling the amount of reagent added to the reactant, it is possible to detect the point at which the indicator changes color. This should be the point where the reactant and reagent neutralize each other, and by reading the scale on the burette, the volume of reagent can be measured.

  7. Titration Practice M1V1 = M2V2 OR M acid V acid = M base V base M = concentration V = volume

  8. Titration Practice • What is the molarity of a CsOH solution if 30.0 mL of the solution is neutralized by 26.4 mL of 0.250M HBr solution? • What is the molarity of a nitric acid solution if 43.33 mL of 0.100M KOH solution is needed to neutralize 20.0 mL of HNO3?

  9. Titration Practice • What is the concentration of a household ammonia cleaning solution of 49.9 mL of 0.59M HCl is required to neutralize 25.00 mL solution? • What is the molarity of an NaOH solution if 50 mL of the solution is neutralized by 37 mL of 0.5M HCl?

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