Titration – process of determining the volume of a standard solution that will be required to react completely with a a mesured amount of a sample

containing the substance under analysis.

A measured volume of the vinegar is placed in a flask.

5.0 mLA few drops of phenolpthalein areadded

After an initial buret reading, standard solution of 0.1N NaOH is added slowly

Near the end of the titration the indicator momentarily changes to pink but goes back to colorless with swirling

When the end point is reached (equivalence point), a tiny excess of OH- is present, shown by the permanent change of color to pink.

The difference between the final buret reading and the initial buret reading gives the volume of the standard NaOH used

35.2 mL

At the equivalence point

Amount of solute (standard solution) = amount of solute (unknown sample)

Number of meq (std soln) = number of meq (unknown sample)

N V (Std. soln) = N V (unknown sample)

Determination of the N of CH3COOH in vinegar

N V CH3COOH = N VNaOH

Titration Process

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