Question

The Marble statues are often slowly corroded when kept in open for along time.Give Suitable reason. 

Answer 1

the gaseous oxides (co2 , no2 and so2) present in air as chemical pollutant mix with water in air to form acids such as ca(hco₃)₂ , hno3 and h2so4. this come down and cause corrosion of marble statues. 

Answer 2

The “Marble statues” are often ‘slowly corroded’ when kept in open for a long time.  

This is because of formation of secondary air pollutants like acids (carbonic acid, nitric acid, sulphuric acid, etc.) which are formed by the reaction of primary air pollutants like carbon dioxide, nitrogen dioxide, sulphur dioxide, etc. respectively with atmospheric moisture and then come down as “acid rain”.

Acid rain has the ability to corrode marble because of which it gets ‘corroded’ when kept in open for a “long time”.