Science Questions

What happens in scientific terms in a reaction between acid rain and limestone? Joyce

Limestone is mostly made up of the mineral calcium carbonate ( CaCO ₃ )  this is not very soluble so the rocks don't dissolve very quickly. If you add an acid however you add Hydrogen  Ions ( H⁺ ) which will react with the carbonate to form hydrogen carbonate HCO₃^- ions which are very soluble in water, and the limestone will dissolve. Or if there is more acid about the two Hydrogen ions will react with a carbonate to form H₂CO₃ which will decompose to form carbon dioxide CO₂ and water H₂O.

The acid can come from a variety of sources sulphur and nitrogen oxides released by burning fuels will form sulphuric and nitric acids, can carbon-dioxide can dissolve in water to form carbonic acid.

June 2008