Answer to Question #32074 in Chemistry for toby

Question

what are the advantages and disadvantages of ethanoic acid(vinegar or acetic acid) ,citric acid and sulfamic acid used as descalers in coffe machines ?
also ,how these three acids remove limescale?
please can you answer this in detail and please can you show me where you got this information from [source} . thank you

Answer 1

Acetic acid, more correctly called ethanoic acid,is a weak acid which will dissolve limescale, which is mostly CaCO₃. Acetic acid CH₃COOH is a weak acid with one ionizable proton which will react with carbonates to produce a solution calcium acetate and CO₂ gas.

2CH₃COOH(aq) + CaCO₃(s) --> (CH₃COO)₂Ca(aq) + CO₂(g) + H₂O(l)

Since all acids react with carbonates to produce CO₂, the best acids to use are those which are least toxic. Acetic acid is found in vinegar which is used to flavor the food we eat. Acetic acid, as vinegar, is a common choice for removing limescale because of its cheap cost and ready availability.