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A student rinsed the apparatus before starting an acid-base titration - AQA - A-Level Chemistry - Question 36 - 2020 - Paper 3
Question 36
A student rinsed the apparatus before starting an acid-base titration. The results of the titration showed that the volume of acid added from the burette was larger ... show full transcript
Worked Solution & Example Answer:A student rinsed the apparatus before starting an acid-base titration - AQA - A-Level Chemistry - Question 36 - 2020 - Paper 3
Step 1
Which is a possible reason for this?
Answer
The most plausible reason for the larger volume of acid added is that D. The burette was rinsed only with water.
When a burette is rinsed with water, residual water can mix with the acid. This can lead to an inaccurate concentration of the acid being measured, thereby resulting in a larger volume being used during the titration. If the titration had been performed with a diluted solution (due to the water), it would require more of the acid to reach the endpoint, causing the volume measured from the burette to be larger than expected.