In your book, I would recommend you use the word "corrosive" instead of
"caustic" as it is a more technically correct term. "Caustic" is usually
reserved for high pH (alkaline) materials, whereas "corrosive" covers any
material that has a deleterious effect on other materials. We say, for
example, "caustic soda" which is sodium hydroxide, a very corrosive alkali,
etc. We wouldn't normally say "caustic" for sulfuric acid, which is highly
corrosive.
One other point: oxalic acid is not a "form" of potassium oxalate, oxalic
acid is the acid which, when combined with potassium becomes potassium
oxalate. When potassium oxalate is dissolved in water, the compound
dissociates into potassium ions and oxalate ions; as the potassium has
higher energy than the oxalate (a weak acid), the potassium hydrolyzes to
potassium hydroxide, making the solution highly alkaline, and very
corrosive. At normal temperatures, the process is infinitely reversible. In
solution, of course, there would be no airborne contamination, but
potassium oxalate, oxalic acid, and potassium hydroxide are all extremely
toxic when taken internally.
<<sil>>
<silh@iag.net>
<webmaster@psa-photo.org>
Sil Horwitz, FPSA
Technical Editor, PSA Journal
check out <http://www.psa-photo.org>