| From: | Marc Renouf renouf@********.com |
|---|---|
| Subject: | rRe: Chemistry Mixup |
| Date: | Wed, 7 Jun 2000 14:12:36 -0400 (EDT) |
> Salt Water is anything but neutral. It's an ionized solution. I think
> you may have forgotten something somewhere along the line. Either that
> or I have, but I'm VERY certain that salt water isn't neutral. Hence
> the corrosive power of salt water in comparison to fresh water (about 4
> times greater actually).
Actually, Salt water is perfectly neutral. Observe a basic
high-school chemistry experiment:
Take concentrated Sodium Hydroxide (NaOH). Very basic, very
nasty. It's most common household use is as the active ingredient in
"Drano."
Add a few drops of Phenolphthalein. The solution should turn
bright pink, and will remain pink as long as the solution is basic (or
nearly basic. Phenolphthalein has an indicator point that's a pH of
between 7 and 8.
Now start adding drops of concentrated Hydrochloric acid. Little
by little, the pink solution should go away. When it turns clear, you're
at a point where the free Na+ ions balance the free Cl- ions. i.e., you
have salt water. Pure, prefectly balanced salt water has exactly the same
pH as pure distilled water - a flat 7.
Why is salt water more corrosive than fresh water? It has nothing
to do with pH. It has to do with the chemistry behind a galvanic
reaction, which behaves differently than an acidic reaction.
Marc
