Which reacts more vigorously with limestone: glacial acetic acid or 5% acetic acid?

If one were to combine glacial acetic acid with limestone powder, what product and biproducts would occur? If you combined vinegar (5% acidity) and limestone? GC

With a solution of acetic acid (ethanoic acid) the vinegar solution and the limestone (calcium carbonate) will undergo the following reaction:

2 CH₃COOH + CaCO₃ (CH₃COO)₂Ca + CO₂ +H₂O

So the products are a salt : Calcium Ethanoate ( this could be extracted by evaporation), the co-products are carbon dioxide ( a gas which causes the solution/substance to effervesce as it is produced) and finally water is also produced.

This is a good test for rock containing carbonates,add a few drops of acid and look for "fizzing".

With the pure Glacial Ethanoic acid ( solid below 16.6 degrees C) without water the molecules do not dissociate to produce the hydrogen ions required for the above Acid/Carbonate reaction so no reaction is anticipated.

( NOTE: Jimmy Says "If the Glacial Ethanoic acid freezes it's time to put the central heating on !")

Author: Jimmy Frinton jimmy@super.powernet.co.uk

General Chemistry Online! Which reacts more vigorously with limestone: glacial acetic acid or 5% acetic acid?