When marble chips (calcium carbonate) are reacted with sulphuric acid, the reaction stops immediately. Why?? :confused:

I believe that the salt formed will form an unreactive layer on the marble chips, which means that the acid cannot react with any of the marble further down.

I'm a little rusty so this may not be right, but it makes sense :)

Kk thanks I think that's right

An impervious layer of Calcium sulphate is formed around the marble chips. No further reaction can therefore take place since no more calcium carbonate particles are exposed to the acid. Nitric acid and hydrochloric acid will carry the reaction to completion.