Protocol for Practical Classes
Subject: pH and buffers
Experiment 4 - Titulation
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Materials: 2.5 mL de vinegar Bequer distilled water |
NaOH 0.08M solution phenolphtalein (pH indicator) pippete pasteur pippete |
Metods:
Put 2.5 mL of vinegar in a bequer
Boil 30ml of distilled water in a bequer
After boiling, cool it again to standard temperature and add 25ml of it to the bequer containning vinegar.
Add 5 drops of phenolphtalein
Add NaOH (around 15 ml and then drop by drop), mixing it untill the color turns to pink.
Write domn the toal amount of NaOh used (45 drops=3ml)
Using the data collected (the solutiuons amounts used) and the given data bellow, calculate the percentage of acetic acid in the vinegar.
Objectives:
To understand how the phenolphtalein can act as a pH indicator
To caractherize the vinegar as an acetic acid solution.
To understand why there was a a color change.
Report suggestions:
Calculate the percentage of acetic acid in the vinegar knowing that:
MM of the acetic acid : 60,0
acetic acid density : 1,049 g/cm3
Explain why the water was boiled and then cooled again before utilization.