Marble dissolution, hydrochloric acid

As first example we consider the dissolution of limestone or marble in hydrochloric acid (Fig. 4). 

Fig. 4 Dissolution of marble in hydrochloric acid, if hydrochloric acid, an aqueous solution of hydrogen chloride, HCl, is poured over marble, foam develops that contains carbon dioxide. HCl is a strong acid and is entirely dissociated into hydrogen and chloride ions, H+ and Cl . The H+ ions are responsible for the reaction while the CT ions remain more or less inactive.

Dissolution of marble in hydrochloric acid. If a few pieces of marble are put in hydrochloric acid, a strong effervescence of carbon dioxide can be observed. 

The rate of dissolution of marble (CaC03) in hydrochloric acid is an example of a chemically controlled reaction. The rate can be measured from the evolution of carbon dioxide. Palmer and Clark found that the rate of dissolution of silica in hydrofluoric acid was proportional to surface area and acid concentration. The rate of reaction was measured by noting the increase in conductivity of the solution... 

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