Path: utzoo!attcan!uunet!kitty!larry
From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.electronics
Subject: Re: Caution: electolysis of water
Summary: Decomposition products of electrodes...
Message-ID: <2852@kitty.UUCP>
Date: 21 Dec 88 20:26:41 GMT
References: <2479@ddsw1.MCS.COM> <849@inuxm.UUCP> <7395@watcgl.waterloo.edu> <15107@mimsy.UUCP>
Organization: Recognition Research Corp., Clarence, NY
Lines: 32

In article <15107@mimsy.UUCP>, chris@mimsy.UUCP (Chris Torek) writes:
> In my young and innocent (hah) days (when I was about 12 or 13), I
> played with electrolysis using the 117 volt line---much faster than
> batteries.  Anyway, I vaguely remember that salt water formed a green
> scum.  I guess now that it must have been choride salts of metallic
> ions in the tap water....

	What you saw was probably cupric chloride resulting from
decomposition of the copper wires which you (probably) stuck in the
solution as "electrodes".  If the water was particularly hard, some
cupric carbonate may have also formed; cupric carbonate is insoluble
in water and would definitely precipitate out.

	When I was a kid in high school, I went "big time" in
electrolysis experiments: I melted table salt in a crucible using my
father's Prestolite (acetylene) outfit, and used carbon electrodes
salvaged from batteries to produce chlorine and metallic sodium.
The sodium production was rather inefficient, but I got enough to
prove the point :-)  N.B.: I don't recommend this as a home experiment;
also, a propane torch will most likely have insufficient heat output
to adequately melt and fuse the salt.

	I always wanted to take the next step and use potassium fluoride
to make fluorine, but I chickened out after finally managing to acquire
the potassium fluoride.  My one and only direct experience with pure
fluorine when I was a grad student convinced me that I had made the right
decision several years earlier. :-)

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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