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A student titrated 25 mL aliquots of three different concentrations of an organic acid against a standardised potassium hydroxide, KOH, solution - VCE - SSCE Chemistry - Question 23 - 2021 - Paper 1
Question 23
A student titrated 25 mL aliquots of three different concentrations of an organic acid against a standardised potassium hydroxide, KOH, solution. The student’s resul... show full transcript
Worked Solution & Example Answer:A student titrated 25 mL aliquots of three different concentrations of an organic acid against a standardised potassium hydroxide, KOH, solution - VCE - SSCE Chemistry - Question 23 - 2021 - Paper 1
Step 1
Sample 2 is the most concentrated acid.
Answer
To evaluate this statement, we need to compare the average KOH titres for each sample. The average KOH titre for Sample 1 is 20.37 mL, for Sample 2 is 19.98 mL, and for Sample 3 is 21.55 mL. Since a higher KOH titre indicates a stronger acid concentration, Sample 3 has the highest KOH titre. Therefore, Sample 2 cannot be the most concentrated acid, making this statement false.
Step 2
Sample 3 is the most concentrated acid.
Answer
Considering the average KOH titres, Sample 3 has the highest average titre at 21.55 mL, indicating it is indeed the most concentrated acid among the three samples. This statement is consistent with the results shown in the table and is therefore true.
Step 3
Step 4
The averages in the table are correct as the results are concordant.
Answer
A concordant set of results is indicated by titrations that yield similar averages within a close range. The average titres for all samples vary only slightly, indicating a consistent method was used. Hence, this statement is true.