The objective of this experiment is to calculate the % purity of aspirin, by first neutralizing the acetylsalicylic acid with excess sodium hydroxide, and then back titrate the excess

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The titration of aspirin

Objective :  

The objective of this experiment is to calculate the % purity of aspirin, by first neutralizing the acetylsalicylic acid  with excess sodium hydroxide, and then back titrate the excess base with standardised hydrochloric acid.

Apparatus :

burette, pipette, volumetric flask,  funnel.

Procedure :

1)   About  1.5 gm  of aspirin was accurately weighed, the mass was recorded.

2)   The weighed amount of aspirin was transferred  into a beaker ,    25 cm3  of

1 molar NaOH was then transferred into the beaker.  The beaker was then gently heated for 10 minutes.

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3)   After heating, the solution was then transferred into a volumetric flask via a funnel. More distilled water was then added to the flask  to make a final volume of 250 a cm3.

4)  25 cm3 of  the above solution was pipetted into a conical flask.

5)  A titrating burette was then set up.  First of all it was rinsed with the 0.1 M HCl, before the whole burette was filled with the acid.

  1. Three drops of phenolphthalein to the conical flask.  The solution is now pink in colour.

  1. The base solution in ...

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