Question

excess of CO2 with carbonic acid.what is formed

Answer 1

CaCO3 + excess CO2 - - - - - - - - - - >Ca(HCO3) 2

Answer 2

H2CO3+CO2 ====> 2CO2+H2O

carbonic acid+carbon dioxide====>
carbon dioxide +water

This reaction leads to acid rain.

hope this helps!!!