[Lars Fred riksson]

I am considering demonstrating the Dumas reaction to my chemistry students.

In this reaction methane is formed in a reaction where sodium acetate and sodium hydroxide are heated together. The methane gas formed is then collected in a large beaker with water and a detergent and then the gas ignited to demonstrate that a hydrocarbon is formed.

I thought the demonstration seemed great, but then it crossed my mind that much (most) NaOH made here in Europe is made using the mercury chlor-alkali process, and that a minute residue of metallic mercury is always left in the lye.

The combination of heating, making methane, and then igniting that very methane seems to suggest that the traces of the indeed volatile Hg can combine with the methane and making the extremely toxic methyl mercury.

Is this a real risk or is the demonstration safe from a mercury perspective using a hume hood?

And yes, in this case I would certainly have preferred American NaOH which is made using an asbestos diafragm instead of mercury...

[chenbeier]

I dont see any problem. What Is the spec. of your NaOH regarding mercury. The mercury is used as metal during electrolysis. There are no mercury compounds.
NaOH is also used in food industry, never heard of poisoning by mercury.

[Lars Fred riksson]

Thanks!