chem 高手請~

CaCO3 + H2CO3 → Ca(HCO3)2
CaCO3(碳酸鈣)遇上H2CO3(碳酸)會生成Ca(HCO3)2 (碳酸氫鈣)
這是碳酸鈣(即大理石/石灰石/白堊)被酸雨(含碳酸的雨)侵蝕的化學式

H2CO3 → H2O + CO2 (reversible)
CaCO3 + H2O + CO2 → Ca(HCO3)2
that is, calcium carbonate dissolves
because calcium hydrogencarbonate is soluble

I just wonder do you mean:

When excess CO2 is added into lime water:

CaCO3(s) + H2O (l) + CO2(g) --> Ca(HCO3)2(aq)

The lime water will be cleared again, because Ca(HCO3)2 is soluble.