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TitleAnalysis of Aspirin Tablets
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Procedure:

1. Finding the total amount of moles of NaOH

1. Standardize the approximately 1.0 M NaOH used for the hydrolysis as follows.

a. Using a pipette filler, pipette exactly 25cm3 of the approximately 1.0 M NaOH
solution into a 250 cm 3 standard volumetric flask and make up to the mark
with distill water.

b. Pippette 25cm3 of this solution into a conical flask and put 2-3 drops of
phenolphthalein indictator Now titrate it against 0.10 M hydrochloric acid .
(See fig. 10a and 10b 11,12)

c. Carry out one rough titration and two accurate titrations. Record your results.
If the two accurate readings does not correspond by less than 0.5 cm3 then do
another one until two consecutive results is abtained.

d. (The rough can be determined by pouring the HCl from the burette until the
endpoint reaches). Then record at which reading it occurs.

e. Then for the accurate ones, pour some the HCl from the burette into the
conical flask until there is a difference of about 5-6 cm3 from the endpoint
(base on the rough titration. Then to reach the end point pour drop wise.

f. Once the titrations are finished, discard the solution from the standard flask.

Description Initial Reading Final Reading Volume of HCl
Rough
First Titration
Second Titration
Third Titration
Average

Table 1

2. Hydrolyze the aspirin as follows.

a. Weigh accurately between 1.3g and 1.7g of the Aspirin tablets into a dry and clean
conical flask. Record the mass of aspirin tablets taken. (Remember to press the zero
button on the scale so that the weigh of the conical flask is not taken.

b. Using a safety filler and a pipette, pipette 25cm3 of the approximately 1.0 M NaOH
on to the tablets, followed by about the same volume of distilled water.

c. Simmer the mixture gently for 10 minutes to hydrolyze the acid. Take a typing sheet
and fold it lenghtwise for about 4-5 foldings. heat over the flame but do not make

Analysis of Aspirin Tablet 54

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