Chemistry Report: Determining Acetic Acid Levels in Different Vinegars

This chemistry report details an experiment conducted to determine and compare the amount of acetic acid present in white and apple vinegar. The aim was to investigate how manufacturing and processing influence the acetic acid content. The experiment utilized acid-base titration, where a sodium hydroxide solution was titrated against the vinegar samples. The procedure involved careful measurements, the use of a phenolphthalein indicator, and multiple trials to ensure accuracy. The results, presented in tables and titration curves, revealed that white vinegar had a higher concentration of acetic acid than apple vinegar. The discussion section linked this difference to the distillation process that white vinegar undergoes, leading to greater purification and concentration of acetic acid. Potential errors, such as parallax and indicator timing issues, were also discussed, along with suggestions for improving the experiment. The report concludes that manufacturing processes affect the acetic acid content, with implications for vinegar's use as a cleaning agent and for medicinal purposes. References include sources on acid-base titration and related laboratory experiments.

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Student Name: Class
Year 11 CHEMISTRY
Assessment Task 2-19 DEPTH STUDY
SCIENTIFIC REPORT
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Title:
Experiment to determine the amount of acetic acid in a white and apple vinegar.
Aim:
Introduction:
1To investigate how manufacturing and processing affect strength of acetic acid between
the two types of vinegar (white and apple) vinegar.
The purpose of the experiment is to investigate how manufacturing and
processing affect strength of acetic acid between the two types of vinegar
(white and apple) vinegar. The practical was conducted in a chemistry
laboratory. Acid-base titration being the principle knowledge used in conducting
the practical.

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Hypothesis:
Equipment Used:
Safety goggles a funnel Phenolphthalein indicator
0.1312 molar sodium hydroxide solution Distilled water.
250 ml conical flask Stirring rod
White tile, clamp, boss and retort stand 50ml burette
Laboratory coat, rubber gloves 25 ml pipette and a pipette filler
Method:
The greater the purification of the vinegar the higher the amount of acetic acid.
Titrating vinegar (acetic acid) in a burette against a 0.1312 molar sodium
hydroxide (titrant) in a conical flask.
Procedure
 Wear safety goggles, laboratory coat and gloves because you are
handling sodium hydroxide and any accidental spillage on your body part
must be washed off with adequate running water.
 Attach the burette vertically using the clamp using boss, clamp and retort
stand.
 Put a white tile on the base of the stand and place a conical flask on top
of it.
 Using a pipette and a pipette filler, siphon 25 ml of 0.1312 molar sodium
hydroxide and pour it into the conical flask and add 2 drops of
phenolphthalein indicator into it.
 Pour vinegar into a burette with an aid of a funnel and mark it.
 Mark the readings on the burette before and after starting titration.
 Start the titration while stirring the solution in the conical flask till end point
when the pink-red solution turns colorless.
 Record the readings on the burette, refill the burette, pour out the solution
in the conical flask and rinse it with distilled water. Then repeat the
procedure once again.

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Scientific Diagram of Experiment set up:
Titrant= vinegar
Analyte= sodium hyroxide

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Risk Assessment: (Explain any actions you had to take to make sure this experiment is safe)
Sodium hydroxide is caustic, it irritates the skin and can cause burns. 0.1312
molar is relatively safe to work with under safe conditions due its diluted nature.
Disposable polythene gloves may be safe to use.
Think about what the safety risks might be in your experiment. Identify safety
measures you could take to make the experiment safer.
Wear safety goggles, laboratory coat and gloves because you are handling
sodium hydroxide and any accidental spillage on your body part must be washed off
with adequate running water

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Describe how you have mad e sure your experiment is fair by identifying the following:
Independent Variable:
Dependent Variable:
Control (if appropriate):
Volume of the reactants.
PH
Phenolphthalein indicator.

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Results: Present your results in an appropriate format. Include a sketch of your titration curve.
Burettes readings (ml)
Initial 4.00 3.70 3.50
Final 7.70 7.50 7.30
Titre 3.70 3.80 3.80
Average titre 3.73
Table 2.
Cornwell’s white vinegar
Burettes readings (ml)
Initial 3.80 3.65 3.55
Final 7.30 6.90 7.00
Titre 3.50 3.25 3.35
Average titre 3.37
Calculations: Moles in 25 ml of NaOH.
Moles present in 25 ml of 0.1312 moles of NaOH.
0.1312 moles.……. 1000 ml
?? moles……...........25 ml
answer =25 ml∗0.1312 mol
1000 ml
= 0.00328 moles
CH3COOH (aq) + NaOH (aq) CH3COONa (aq) + H2O (l)
Mole ratios between the two reactants = 1: 1
Therefore, the moles of:
Acetic acid in 3.73 ml of Cornwell’s apple vinegar
answer =1 x 0.00328 mol
1
= 0.00328 moles.
Molarity of acetic acid in Cornwell’s apple vinegar is;
0.00328 moles…………3.73 ml
?? moles…………………1000 ml
answer =1000 ml∗0.00328 mol
3.73 ml
= 0.8794 moles, therefore its concentration= 0.8794 M
Calculation of molarity of Acetic acid in 3.37 ml of Cornwell’s white vinegar

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Figure 2. Titration curve of white vinegar with sodium hydroxide
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
Titration curve of white acetic acid with sodium hyroxide
(3.53 mL, 0.9733 mol/L, with 0.1312 mol/L NaOH)
Volume of white vinegar (mL)
pH
Blue arrow indicates point of equivalence at 3.53 ml
Figure 3. Titration curve of apple vinegar with sodium hydroxide
1

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0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0 Titration of acetic acid with sodium hyroxide
(3.73 mL, 0.8794 mol/L, with 0.1312 mol/L NaOH)
Volume of apple vinegar (mL)
pH
Blue arrow indicates point of equivalence at 3.53 ml

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Discussion:
Briefly summarize your results.
Outline any errors that could have occurred and how they would have affected your experimental
results.
The Cornwell’s white vinegar has a higher amount of acetic acid than of Cornwell’s apple
vinegar. This is due to the fact that white vinegar and apple vinegar undergoes almost the
same process during production. 2White vinegar undergoes distillation after fermentation
which results in further purification of the product thus concentrating it. This therefore,
results in a higher amounts of the acetic acid in the white vinegar as opposed to apple.
Parallax error: results in poor taking of readings due to improper reading of the
burette
Poor timing of the indicator colour change which results in excessive or
additional drops of vinegar being added into the already neutralize solution.
Faulty apparatus.

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Based on your results, explain any changes you could make to further improve your experiment.
Diluting the vinegar samples to improve their accuracies

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Now you have completed this experiment are there any other experiments you could do to further
investigate this idea or are there any real-world applications of this principle?
Assess your method by considering:
Reliability:
Accuracy:
The difference in the acetic acids in the two samples has resulted to white vinegar
being used as a cleaning agent. On the contrary apple vinegar is being used for
medicinal purposes due to it low acetic acid content and un adulterated nature.
The method is reliable as long as there is proper readings and use of equipment. Titration
has been tested and proven to produce outstanding results.
The method is less accurate due to sodium hydroxide prepared being of very low PH and
the acid (vinegar) being strong acid. Diluting vinegar will really improve accuracy. Proper
use of equipment and good reading of apparatus will improve this too.