Magnesium Bicarbonate and Ascorbic Acid Reaction [closed]








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30 ml. Magnesium Hydroxide USP is added to 2 l. carbonated water to make magnesium bicarbonate to be used as a highly bio-absorbable Mg dietary supplement. I'm told the result is 90 mg. elemental Mg per each 4 oz. of this "Magnesium Water."


If one gram of ascorbic acid is added to a small amount of this Mg solution that has been diluted with filtered tap water, the solution becomes fizzy releasing CO2. I didn't measure the amount of Mg solution or the amount of water, but it was approximately 2 tablespoons of dilute solution with one gram (measured) vitamin c crystals. I do understand this release of CO2 is due to the acid-base reaction.


How are the ascorbic acid and the magnesium changed in this solution? Is there still any vitamin C in the solution? What form of Mg is the result? 


This is not a homework question. It's just for personal curiosity, but I only took two semesters in chemistry in the early 80's so my knowledge of the subject is very limited. Sorry if this is the wrong place for such a question. You can delete it.




Ascorbic acid reacts with bicarbonate:


$$\ce{H2Asc + 2 HCO3- -> Asc^2- + 2 H2O + 2 CO2 ^}$$


Ascorbate as a strong reduction agent reacts with oxygen:


$$\ce{2 Asc^2- + O2 + 2 H2O -> 2 DHA + 4 OH-}$$


where $\ce{DHA}$ is dehydroascorbic acid.


If the ascorbic acid solution is alkalized by sodium hydroxide, the solution slowly turns yellow as the result of the oxidation progress.


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