The marble statue often slowly get corroded when kept in open for long time . Assign sutiable example.
SO2, NO2 gases are released into the atmosphere from various sources. These dissolve in rain water to give acid which corrodes marble statues.
2SO2 + O2 -------> 2SO3 ; H2O+SO3 ------> H2SO4
2NO2 + H2O -------> 2HNO3
CaCO3 + H2SO4 -------> CaSO4 +H2O + CO2
CaCO3+2HNO3 -------> Ca(NO3)2+H2O+CO2