Chemical Reactions That Occur Between Marble & Sulfuric Acid

Corrosion Reaction

• Despite being considered a strong and highly durable material, marble is in fact very soluble, even in weak solutions of acid. When a solution of liquid sulfuric acid comes into contact with solid marble, a corrosion reaction occurs. The sulfuric acid dissolves and breaks apart the calcium carbonate -- the chemical name for marble -- molecule. In doing so, it also breaks its own bonds and forms a suspension of positively charged calcium ions and negatively charged sulphate ions in the sulfuric acid solution.

Other Products

• In order to cause the ionic suspension of the calcium ions and the sulphate ions in the solution, the reaction must also release the other atoms that made up the constituent reactants. The reaction began with one calcium atom, one carbon atom and three oxygen atoms in the marble and two hydrogen atoms, one sulfur and four oxygen atoms in the sulfuric acid. One of the calcium atoms and the sulphate component -- one sulfur and four oxygens -- are accounted for; the other atoms are not. The freed hydrogen from the sulfuric acid immediately reacts with the freed oxygen from the marble to create water. This leaves just the carbon and two of the oxygen atoms from the marble, which are released as carbon dioxide.

Occurrence in Nature

• The main instance of a reaction between sulfuric acid and marble in the real world is due to acid rain. The problem of acid rain has been steadily growing since the world entered the industrial age. The problem occurs when sulfur dioxide is released following the combustion of fossil fuels in factories and becomes dissolved in water. This creates sulfuric acid, which is then washed into the water table, polluting rivers, lakes and soil. Often, this sulfuric acid is evaporated and falls as weakly concentrated acid rain. If this falls on marble structures -- and many buildings are constructed of marble -- it corrodes it, initially making inscriptions and ornate carvings difficult to distinguish, before eventually threatening the structural integrity of the building itself.

Marble and Limestone

• Marble and limestone share the same calcium carbonate formula. Therefore, limestone buildings are susceptible to acid rain, as well. The two materials differ slightly only in structure. Both have a crystalline structure, but the crystals in marble are much larger, giving it a smoother, glossier effect. Limestone, on the other hand, has smaller crystals, which give it a rougher, coarser texture. As a result, limestone has larger pores and a more exposed surface area, making it even more vulnerable to the effects of acid rain. Marble, with its smaller pores, can deflect much of the rain with its smooth surface; however, it will still succumb if it endures prolonged exposure to acidic rain.