John B. Paine III on sun 15 oct 00
Hi all: In response to Stacey Lynn Klopp, and as an addendum to Cindy
Strnad's advice from the home of Custer Spar (Cindy: give my regards to the
Bull Moose and Tin Mountain pegmatites, among others!), I have a few things
to add about hydrochloric acid. It is indeed available from building supply
houses, but usually goes under its archaic name of "Muriatic Acid". I buy
mine from Home Depot. It is offered in gallon size, one of which costs less
than three dollars. Its primary purpose is for pH control of swimming
pools. The Home Depot product is of "20 degrees Baume" (a French word with
'accent aigue' on the 'e' ) in concentration, which is around 31% hydrogen
chloride (HCl) by weight. By contrast, typical laboratory reagent
hydrochloric acid is saturated with hydrogen chloride, affording a 37 to 38%
by weight concentration of HCl, and fumes badly in air every time the bottle
is opened. Although the "20 Baume" product does not fume visibly when the
bottle is opened, its sour aroma is apparent whenever the bottle is open.
Hydrogen chloride fumes are enormously corrosive, and will cause even
stainless steel to rust. Therefore, this is not a product to be stored
inside a residence, or in the presence of steel tools. Hydrochloric acid is
corrosive, but not toxic in small amounts (remember always the toxicological
dictum of Paracelsus that "the dose makes the poison"). Remember also that
it is a component of stomach acid. [I remember my godmother's aunt having
to drink the stuff through a glass straw during mealtime to correct a
digestive deficiency about 35 years ago.] The Home Depot product is of high
quality, and essentially colorless, which fact is readily apparent through
its translucent polyethylene bottle. I store mine further enclosed in a
large polyethylene trash barrel with cover, kept outside in a protected
area. Whenever I use the product, it is always inside a large polyethylene
or polypropylene tray intended to contain any spillage. Spillage can be
neutralized with baking soda (sodium bicarbonate) or whiting (calcium
carbonate); both will effervesce (give off carbon dioxide) upon reaction,
and a minor aerosol may form as a result.
Some "Muriatic Acid" is offered at lower concentration (e.g. 20% by
weight), and in an opaque plastic bottle. One may find upon examining the
contents more closely, that such products tend to be bright yellow in color.
This is due to the presence of small amounts of iron in solution: the
tetrachloroiron(III) monoanion is an intense yellow. I suspect that the
opaque bottle is designed to hide the color of what is obviously a less pure
product.
While on the subject of chemistry, I have one observation to make about
manganese. You ingest small amounts of this element every time you eat
anything green. This is because manganese is intrinsic to the active site
of "Photosystem II", which is where the plant is converting water to
molecular dioxygen.
Best regards to all,
John B. Paine III, Ph.D. (Organic Chemistry)
Senior Research Scientist
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