Question

94. Marble statues often slowly get corroded when kept in open for a long
time. Assign a suitable explanation​

Answer 1

Marble statues often slowly get corroded when kept in open for a long time.

Marble Statues are made up of Calcium Carbonate, when they are kept in open environment they get acted upon by the acidic compounds present in air causing reaction between Calcium Carbonates and Acids which in turn causes Corrosion.

Answer 2

Answer:

Taj Mahal is an example of corrosion of marble. The discoloration of its marble is due to corrosion.  Air primarily consists of various pollutant gases like carbon dioxide, nitrogen dioxide, Sulphur dioxide  etc which mix with moisture in air to form acids such as carbonic acid, nitric acid and sulphuric acid.  This acid comes down as acid rain and causes corrosion of marble statues and monuments. Marble which  is composed of calcium carbonate reacts with the different acids which is given as follow:-

CO2 + H2O + CaCO3→ Ca (HCO3)2