I am doing a Chemistry IA on the stability of ascorbic acid in different pH, and found that the stability decreased (there was a lower final concentration of ascorbic acid) as pH increases. Why is this so?
The decrease of ascorbic acid is probably mostly due to oxidation.
Oxidation is loss of electrons.
Increased pH means more ascorbate, thus negative charge and higher electron density.
Higher electron density means easier loss off electrons, thus more oxidation and less ascorbic acid at the end.