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Question
What are the products formed in sequence when excess of CO2 is passed in slaked lime?
Options
\[\ce{CaCO3, Ca(HCO3)2}\]
\[\ce{Ca(HCO3)2, CaCO3}\]
\[\ce{CaO, CaCO3}\]
\[\ce{CaO, Ca(HCO3)2}\]
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Solution
\[\ce{CaCO3, Ca(HCO3)2}\]
Explanation:
Slaked lime is an aqueous solution of Ca(OH)2 which is used to identify the `"CO"_3^(2-)` and `"SO"_3^(2-)` ion in the given mixture. If CO2 is passed in slaked lime then following reaction takes place.
\[\ce{Ca(OH)2 + CO2 -> \underset{(Insoluble in water)}{\underset{White}{CaCO3 \downarrow +}} H2O}\]
\[\ce{CaCO3 \downarrow + CO2 + H2O -> \underset{(Soluble in water)}{\underset{Colourless}{Ca(HCO3)2}}}\]
Calcium carbonate causes milkiness to appear, while calcium bicarbonate that is produced when there is too much CO2 is soluble in water. Milkiness vanishes as a result.
