Question

Which salts are responsible for yellow colour of taj mahal?

Answer 1

Calcium nitrate (Ca(NO3)2)(Ca(NO3)2) and calcium sulphate (CaSO4)(CaSO4) are responsible for yellow colour of Taj Mahal in Agra due to acid rain.
The reaction that take place with limestone (marble) are
CaCO3+H2SO4→CaSO4+CO2+H2OCaCO3+H2SO4→CaSO4+CO2+H2O
CaCO3+2HNO3→Ca(NO3)2+CO2+H2OCaCO3+2HNO3→Ca(NO3)2+CO2+H2O.

Answer 2

SO2 gas NO3 etc .gas from industries when mixes with air for acis like sulphuric acid .This Sulphuric Acid Reacts With The Calcium Present In The Stones Of The Taj Mahal To Form Gypsum, Then It Flakes Off.

H2SO4+Ca→CaSO4.H2OH2SO4+Ca→CaSO4.H2O

Acid Rain Is The Reason For This Corrosive Action Of Acid Deposition, Which Is A Result Of Human Activities.