Question

on passing excess co2 through limewater it first turns milky and then becomes colourless ? and write the chemical equations?

Answer 1

When you pass carbon dioxide through this solution, the two compounds carbon dioxide (CO2) and calcium hydroxide (CaOH2) will react to form white and insoluble calcium carbonate which precipitates out of the solution. The reaction is as follows: Ca(OH)2(aq) + CO2(g) →CaCO3(s)↓+H2O This is how the solution looks before and after reaction: When excess CO2 is added, it reacts with calcium carbonate( CaCO3) and water (H2O) to form calcium bicarbonate Ca(HCO3)2 and since it is soluble in water, it dissolves in it making the solution clear again. The chemical reaction is as follows: CaCO3 + CO2 + H2O ---------> Ca(HCO3)2