Passing carbon dioxide gas through calcium hydroxide solution
The reactions occurring in the above Activity are written as –
Test tube A: Na2CO3 + HCl (aq) → NaCl (aq) + H2O (l) + CO2 (g)
Test tube B: NaHCO3 + HCl (aq) → NaCl (aq ) + H2O (l) + CO2 (g)
On passing the carbon dioxide gas evolved through lime water,
Ca(OH)2 + CO2 (g) → H2 O (l) + CaCO3 (s)
(Lime water) (White precipitate)
On passing excess carbon dioxide the following reaction takes place:
CaCO3( s) + CO2 (g) + H2O(l) → Ca(HCO3)2 (aq)
(Soluble in water)
Limestone, chalk and marble are different forms of calcium carbonate.
All metal carbonates and hydrogen carbonates react with acids to give a corresponding salt, carbon dioxide and water.
Thus, the reaction can be summarised as – Metal carbonate/Metal hydrogen carbonate + Acid → Salt + Carbon dioxide + water