On Mon, 29 Dec 2003 04:15:57 UTC, El Caballo Grande
wrote:



Dan Drake wrote:
...
Many treatments for sick fish involve adding sodium chloride to the water,
and I've never yet seen a toxicity warning attached to this advice. I
can't imagine adding so much HCl that it would raise the chloride level
above therapeutic levels.

I'd really like to know what the answer is here, having heard lots of
warnings about too much chloride as well as too much sodium.

The Chloride of salts (such as sodium chloride) in very small amounts is
not going to have a significant effect.
Releasing hydrochloric acid is almost identical to releasing chlorine
gas.

Not identical or all that simlar: chlorine gas is a powerful oxidizing
agent that would burn fish's gills as it burns people's lungs;
hydrochloric acid is just an acid. HCl is a strong acid, with which you
could make a tank so acidic that it would kill the fish, and I don't
recommend its use; but it's just an acid. And the ion it puts in the
water (apart from the acidity) is chloride.

There is a very big difference in activity levels of something
described with a suffix of -ide versus -ic.

A big difference because one suffix denotes an acid and the other denotes
a salt made by neutralizing that acid (in some cases the solution of the
salt is acidic because of hydrolysis, but a lot less acidic than the plain
acid); the negative ion in each is the same. HydroThingic Acid (HThing)
dissociates into hydrogen ion (H+) and Thingide ions (Thing-) .

There are some sharp chemists in these seminars who caught me forgetting
that principal a couple of years ago.

Small amounts of salt introduced into a fresh water setup primarily
effects the osmotic pressure of the cells--less work is expended pumping
excess water out of the fresh water fish's cells to keep them from
bursting when there is a trace of salt in the external water.
Identical amounts of compounds with the suffix -ide or -ine will kill
the creatures outright.

Dunno what you mean by that. Rather, so far as -ide is concerned, this
just isn't so. Salt is soduim chlorIDE. Naturally, chlorINE is entirely
different in its effects.


--
Dan Drake

http://www.dandrake.com

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