Ask an Expert: The titration of ascorbic acid and iodine solution

[Gracie72]

Hi, I conducted a titration of orange juice against iodide solution and got some very strange results. I am investigating how temperature effects the concentration of ascorbic acid in orange juice and all the research I have done suggests that the concentration of ascorbic acid should decrease as the concentration increases. However, with my experiment this was not the case, instead the concentration of ascorbic acid increased as the temperature also increased. I cannot find any other documents online that share these results and need help to justify why this has happened. Please help!

[norman40]

Hi Gracie72,

Ascorbic acid will oxidize or decompose when heated. So the ascorbic acid concentration in orange juice should decrease when the temperature is increased.

Titration experiments can be a bit tricky. You might want to compare your method with the procedures at the following links:

https://www.sciencebuddies.org/science- ... #procedure

https://www.sciencebuddies.org/science- ... -titrating

How did you set up your experiment with different temperatures? Did you allow your juice samples to come to room temperature before titration? Titration samples that are at different temperatures could influence your results.

I hope this helps. Please post again if you have more questions.

A. Norman