3 Dec
2003
3 Dec
'03
7:49 a.m.
On Dec 3, 3:55, der Mouse wrote:
[cisin(a)xenosoft.com]
a
"carbonic acid" is water with CO2 in
suspension??
[vance(a)neurotica.com]
No. Not in suspension. In solution.
It's not quite a solution in the usual sense of the word. More like reaction product - but it's one which is fairly
close to balanced
energically and thus can run either way with relative ease, either
H2O+CO2->H2CO3 or H2CO3->H2O+CO2. (Most reactions run both ways in
theory, but with a large energy difference that makes it easy to run
one way and hard the other. An example is NaOH+HCl = H2O+NaCl+heat,
with the "heat" term large enough, especially compared to the
activation energy, that it's _hard_ to make salt water disassociate
into caustic soda and hydrochloric acid.)
<tongue-somewhat-in-cheek>
Well if we're being picky, then I'd say it *is* a solution in the
normal sense of the word. Carbonic acid is a very weak acid, and the
reaction is firmly in favour of a predominance of CO2 in solution.
For the rest, CO2 and water each dissociate just like any inorganic
compound in water. You don't really form H2CO3, you form 2 x H+ and
CO3--. Similarly, when you have salt water, you have Na+ and Cl-, plus
a few hydrogen and hydroxyl ions, not "molecules" of NaCl. It's not
*that* hard to turn it into NaOH; a 1.5V battery[1] will add electrons,
cause hydrogen to be given off, liberating chlorine as well, and what's
left is Na+ and OH-. See, we're back to electrons again :-)
</tongue-somewhat-in-cheek>
[1] Yes, I know it's a single cell, not a battery :-)
--
Pete Peter Turnbull
Network Manager
University of York