GEOLOGY

Detailed explanation-1: -When sulfurous, sulfuric, and nitric acids in polluted air and rain react with the calcite in marble and limestone, the calcite dissolves. In exposed areas of buildings and statues, we see roughened surfaces, removal of material, and loss of carved details.

Detailed explanation-2: -Caves are formed by the dissolution of limestone. Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves.

Detailed explanation-3: -Water has dissolved the limestone that once occupied this void. When carbon dioxide in the air dissolves in rain, a weak carbonic acid is formed. This weak acid, while harmless to plants and animals, is able to dissolve some kinds of rocks, like feldspar and limestone, in a process called carbonation.

Detailed explanation-4: -Reaction with acids Like all metal carbonates, calcium carbonate reacts with acidic solutions to produce carbon dioxide gas. It is this reaction that is responsible for limestone fizzing when dilute hydrochloric acid is placed on its surface.