From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Chemical removal of rusty spark plug
Date: Thu, 02 Mar 2000 02:19:19 GMT

On Wed, 1 Mar 2000 18:25:17 +0000, Bob Unitt
<junk@bobunitt.demon.co.uk> wrote:

>,;In article <38bf21ec.7972484@news.wcta.net>, Don Wilkins <REMOVE_T
>,;HISdwilkins@means.net> writes
>,;<SNIP>
>,;>
>,;>If you store concentrated nitric acid you should keep it out of the
>,;>light (particularly sunlight).
>,;
>,;Why ?
>,;
>,;Just curious...

Curiosity killed the cat but cats can't type very well so...... your
curiosity should be harmless.

In the presence of sunlight concentrated nitric acid decomposes to
oxides of nitrogen which are gases. This results in a brown color
instead of the colorless product you had before you did such
dastardly and abusive treatment of your pristine and pure nitric acid.

In many cases this isn't going to make a whole lot of difference in
the way the nitric acid will behave when you apply it to do its thing
on whatever.

The problem can arise when you leave it on the shelf in a sealed
bottle. Those gaseous products of decomposition would like to get out
of the bottle and do their thing. Unfortunately there is that damn
cork or worse a tight screw cap preventing their escape.

So they wait patiently until the pressure in the bottle becomes large
enough to rupture the container. AHAH now they are free.

Once it blows you probably would prefer to be elsewhere.