When \( 22.4\text{ L} \) of \( \text{CO}_2 \) gas at STP is passed through an excess aqueous solution of \( \text{Ca(OH)}_2 \), the mass of precipitate formed is:

\( \text{Ca(OH)}_2 + \text{CO}_2 \rightarrow \text{CaCO}_3\downarrow + \text{H}_2\text{O} \). \( 22.4\text{ L} \) of \( \text{CO}_2 \) at STP = \( 1\text{ mol} \). Moles of \( \text{CaCO}_3 \) formed = \( 1\text{ mol} \). Molar mass of \( \text{CaCO}_3 = 100\text{ g/mol} \). Mass = \( 100\text{ g} \).