SecretSquirrel
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Determining the concentration of methoxide solution
Hi fellow amateur chemists!
I got hold of some sodium methoxide solution that was not in its original container and the label said only "NaOMe soln." I have no idea how old this
chemical is nor is it still any good. I want to somehow check the amount of methoxide present (if any) and I'm wondering if anybody knows a simple
analysis method for measuring its concentration. I'd prefer titration or any other simple inexpensive method, friendly to amateur chemist with no
access to fancy analytical equipment.
Any help is greatly appreciated!
[Edited on 11-4-2014 by SecretSquirrel]
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Galinstan
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surely a simple acid base titration will work just use an indicator like phenalthalien and see how much of a known concentration of acid it takes to
neutrlise it.
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SecretSquirrel
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I'm not so sure about that, since sodium methoxide decomposes with water to give sodium hydroxide and methanol. I'm sure some of it already decomposed
over time by absorbing moisture from the air and I would like to know how much methoxide is still in solution. Simple acid titration won't do, because
by doing that I'd be titrating sodium hydroxide already present as well as sodium methoxide. As far as I know titration should be performed in a
non-aqueous medium but I still don't know what this medium should be and what reagent I need to use.
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Galinstan
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titrations don't have to be performed in aquas solution you could do do the titration in methanol using an acid soluble in methanol , but doing it in
water would be fine as adding an excess of water will form equal moles of sodium hydroxide as there where moles of methoxide so you could get your
concentration that way 
EDIT: sorry i missread your last post about the already present hydroxide ,im not sure then
[Edited on 11-4-14 by Galinstan]
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zed
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Fellers here abouts have posted simple methods for making fresh NaOMe. It isn't hard, and cost is minimal. Check the search engine. The topic has
been much discussed.
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