[Nina Choi]

Hello! I'm working on a lab based on the question of how time, temperature and preparation method affects vitamin C content in lemon water, and I observed the change for three days.
Then the most important thing is that I used VITAMIN C TEST STRIPS, not the iodine titration method!!!

And then I was able to come up with two chemical equations.

1) I3^- + C6H8O6 + H2O => C6H6O7 + 3I^- + 2H^-

2) C6H8O6 => C6H6O6 + 2H^+ + 2e^-

However, I don't know which one's correct.
Please tell me the correct one or are they both wrong??

[Borek]

However, I don't know which one's correct.

Correct in what sense and in what context?

First one is definitely wrong - it is not even balanced, and it should contain H⁺ instead of H^- on the RHS. Correcting it it will give a correct reaction of vit C oxidation with iodine.

Second one is a correct half reaction of the vit C oxidation.

Whether they are in any way related to your question I have no idea, as it is not clear what the question is.

[Nina Choi]

Sorry, as I was quite unclear with what I was asking and with my question.
Basically, I did a lab on mixing lemon juice/slice with water, and I observed the results for three days.
I have used vitamin C test strips, not the iodine titration method.

And I meant correct by if it is suitable to my topic. For instance, the first equation is used for iodine titration people say, and the second one does not show water in it, so I assume that it's wrong.

So, if I take out iodine from the first equation and balance it, which would be C6H8O6 +H2O => 2H^+
Is this equation correct and is it suitable for my topic?

[Arkcon]

And then I was able to come up with two chemical equations.

1) I3^- + C6H8O6 + H2O => C6H6O7 + 3I^- + 2H^-

2) C6H8O6 => C6H6O6 + 2H^+ + 2e^-

However, I don't know which one's correct.
Please tell me the correct one or are they both wrong??

Hi there, Nina Choi:.  Briefly, no, your reactions aren't correct.  Look at this online reference:

http://chemistry.oregonstate.edu/courses/ch130/old/VITCTEXT.htm

There's a skeleton formula that discusses what happens when Vitamin C is oxidized.