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Organic acids, including vitamin C (ascorbic acid), are present in lemon juice - VCE - SSCE Chemistry - Question 26 - 2018 - Paper 1
Question 26
Organic acids, including vitamin C (ascorbic acid), are present in lemon juice. Since organic acids and vitamin C are weak acids, they will undergo acid-base reactio... show full transcript
Worked Solution & Example Answer:Organic acids, including vitamin C (ascorbic acid), are present in lemon juice - VCE - SSCE Chemistry - Question 26 - 2018 - Paper 1
Step 1
An acid-base titration with potassium hydroxide and phenolphthalein indicator, and a redox titration with iodine and a starch indicator
Answer
This method involves using a strong base (potassium hydroxide) to neutralize the organic acids present in the lemon juice while employing phenolphthalein as the indicator to signal the endpoint of the titration.
For vitamin C, the iodine-redox titration will help determine its concentration by observing the change when iodine reacts with the ascorbic acid until a starch indicator is added, indicating the endpoint. This method provides a comprehensive analysis of both organic acids and vitamin C in lemon juice.