Sorry, but thats not me. I use the same username as this one(Funky_Fish14) on RC.
Btw Brad, you wrote the molecular formula for acetate as opposed to acetic acid in the first of your last two posts
Acetic(Ethanoic) acid does not 'contain' CO2. There are however multiple ways acetic acid may be written.
A) CH3COOH
B) H3CCOOH
C) C2H4O2
D) CH3CO2H
E) HC2H3O2
The most common/accepted forms are CH3COOH and CH3CO2H. Some prefer to write the latter as H3C2O2H because this matches the molecular structure the best. Ofcourse all the numbers would be written as a subscript. None of these forms 'contain' CO2. There is a very large difference between the molecular formula and the molecular structure. If this was true, many other substances could also be said to 'contain' CO2.
I spoke to some chemistry profs about this topic, here is where the CO2 comes from in the reaction.
Excess Ca(OH)2 reacts with the little amount of CO2 in the water to produce bicarbonate ions. Excess reactions occur (because there is no CO2) and produce Bicarbonate ions. Bicarbonate react with calcium and create Calcium Carbonate and water. The Acetic acid has a tendency to react only with the Carbonate ions that are formed, as opposed to with the hydroxide (OH) ions, which in turn produces a bunch of CO2 required for the reaction with the Calcium Hydroxide (Kalk). This explains why the acetic acid works to dissolve the kalk. That is why it allows a large dose all at once to work. However, dripping a kalk solution in to the water slowly will work fine as well, because the Calcium Hydroxide has enough CO2 throughout the aquarium water to react with and dissolve correctly.
In my previous post in this thread, I had yet to see anywhere online offer any explanation as to why the acid would not react with the base (calcium hydroxide, kalk) right off the bat. My chem profs were able to explain why it works and why it has a tendency to avoid reacting with the Ca(OH)2 immediately. This post clarrifies my last point in my last post, and why adding acetic acid works. So what I initially explained about acid not working was wrong(I knew that it did work in practice, but chemically didnt make sense?), but, apparently it takes a heck of a lot more chem knowledge to understand why its happening.
Cheers,
Chris