"my_2¢" wrote in message
...
Please excuse this question; I realize this must seem elementary but I
am quite stymied and it entails a work related situation.

Cleaning out a acid cupboard where I work there are several bottles of
technical grade HNO3 which would be approx 70% but there are others
which are marked as "Fuming" (current date). My question is does there
exist a simple method to determine the percentage of acid if no
specific gravity info is present (i.e. 1.43, 1.50. etc, etc) ?

There are some other bottles that are student's from last semester
that have a variety of information dealing with temp...can HNO3 be
"cooked" to a higher percentage (exposed to heat, thus reducing the
water content? I was told that under no circumstances to get rid of
the higher percentage grades as they cost quite a bit more money. But
if they can be reduced, why pay for a higher percentage? I am quite
aware of the "kitchen" methodologies of extraction w/ methylene
chloride and destilation but I always wondered why a higher percentage
was simply not produced via evaporation?


I'm no chemist, but my work with precious metals got me somewhat acquainted
with acids. One of the things you get when you buy the higher
concentrations isn't just that, you also pay for the level of purity.
Reagent grade nitric acid was guaranteed to have fewer contaminants, for
which you paid more money. A lot more money. I'm sure that, depending on
the methods employed to manufacture the acids, high levels of quality were
also obtained by tech grades, but there was no guarantee. I can only
assume that it would be much like buying bar stock for the shop. If you
want a guarantee of quality, you buy certified material, for which you pay
slightly more, if not a lot more.

Perhaps someone in the chemical industry will clarify this for all of us.

Harold