Acid Rain Reaction With Marble

Acid precipitation affects stone primarily in two ways.

Acid rain reaction with marble.

Acid base reactions can have a strong environmental impact. The damage that acid rain does to limestone and marble buildings and sculptures is due to a classic acid base reaction. Students know how to calculate ph from hydrogen ion concentration. It is well established that either wet or dry deposition of sulfur dioxide significantly increases the rate of corrosion on limestone sandstone and marble.

What effect does acid rain have on marble. Acid rain has the following reaction with the marble calcium carbonate. How does acid precipitation affect marble and limestone buildings. When sulfurous sulfuric and nitric acids in polluted air and rain react with the calcite in marble and limestone the calcite dissolves.

A chemical reaction equation 9 between calcium carbonate and sulfuric acid the primary acid component of acid rain results in the dissolution of caco. Caco 3 h 2 so 4 caso 4 h 2 o co 2 the formation of calcium sulphate results in the corrosion of this beautiful monument. The reaction of a strong acid with a salt of a weak acid goes to completion. Acid rain contains carbonic nitric and sulfuric acid that are produced by oxidation and dissolution in water of gaseous oxides co 2 no 2 and so 2 present in the air as chemical pollutants.

Students know how to use the ph scale to characterize acid and base solutions. Marble like all calcareous rocks is particularly sensitive to degradation by acid chemicals and to weathering. In exposed areas of buildings and statues we see roughened surfaces removal of material and loss of carved details. Stone surface material may be lost all over or only in spots that are more reactive.

How does this happen. Students know buffers stabilize ph in acid base reactions. Although these are recognized as highly durable materials buildings and outdoor monuments made of marble and limestone are now being gradually eroded away by acid rain. When sulfurous sulfuric and nitric acids in polluted air react with the calcite in marble and limestone the calcite dissolves.

For example a dramatic increase in the acidity of rain and snow over the past 150 years is dissolving marble and limestone surfaces accelerating the corrosion of metal objects and decreasing the ph of natural waters. Acid rains are one of the main degradation agents for marble artifacts. Acids in the rain react with the calcium compounds in the stones to create gypsum which then flakes off. Marble and limestone both consist of calcium carbonate caco 3 a salt derived from the weak acid h 2 co 3.