TITRIMETRIC METHODS OF ANALYSIS

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TITRIMETRIC METHODS OF ANALYSIS

• BASICS OF ANALYTICAL CHEMISTRY
• PROF.DR.ENDANG ASIJATI M.Sc.

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Titrimetric Methods

• Includes a group of analytical methods that are
  based upon determining the quantity of a reagent
  of unknown strength that is required to react
  completely with the analyte.

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Titrimetric Methods

• Volumetric titrimetry
• A type of titrimetry in which the standard
  reagent is measured volumetrically.
• Gravimetric titrimetri
• A type of titrimetry in which the mass of the
  standard reagent is measured.
• Coulometric titrimetry
• A type in which the quantity of charge in
  coulombs required to complete a reaction with the
  analyte is maesured.

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Titration?

• A process in which a standard reagent is added
  to a solution of an analyte until the reaction
  between the analyte and the reagent is judge to
  be complete.
• Back-titration
• A process in which the excess of a standard
  solution used to react with an analyte is
  determined by titration with a second standard
  solution.

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Equivalence and end Points

• Equivalence point
• Related to the amount (mol/mek)
• End point
• Related to the physical sign that associate with
  the condition of chemical equivalence.
• The end point is express in range, the range
  should address to the equivalence point.

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Standard?

• Standard Solution
• A primary standard
• A secondary standard
• Standardization
• A process in which concentration of a volumetric
  solution is determined by using it to titrate a
  known mass of a primary standard.

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PRIMARY STANDARD

• HIGH PURITY
• ATMOSPHERIC STABILITY
• INDEPENDENT OF HUMIDITY
• MODEST COST
• LARGE MOLAR MASS

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ALGEBRAIC RELATIONSHIP

• AT THE EQUIVALENCE POINT
• Equivalent A Equivalent B
• Mol A Mol B (if the reaction is 11)

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TITRATION CURVES FOR WEAK ACIDS

• At the beginning, the solution contains only a
  weak acid or a weak base, and the pH is
  calculated from the concentration of that and its
  dissociation constant.
• After various increment of titrant have been
  added, the solution consists of a series of
  buffers. The pH of each buffer can be calculated
  from the analytical concentration of the
  conjugate base or acid and the residual
  concentration of the weak acid or base.

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TITRATION CURVES FOR WEAK ACIDS

• At equivalence point, the solution contains only
  the conjugate of the weak acid or base being
  titrated, and the pH is calculated from the
  concentration of this product
• Beyond the equivalence point, the excess of
  strong acid or base titrate represses the acidic
  or basic character of the reaction product to
  such an extent that the pH is governed largely by
  the concentration of the excess titrant.

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