A salt X is obtained on reaction of a metal carbonate with an acid . When electricity is passed
through an aqueous solution of X , a gas Y is obtained , which is used for disinfecting water.
(i) Identify X and Y.
(ii) Write chemical equations for the reactions of production of gas Y and reaction between metal
carbonate and acid to produce X .
Answers
Answer:
Calcium carbonate gives carbon dioxide gas when reacts with hydrochloric acid.
CaCO3 + 2HCl ⇨ CaCl2 + CO2 + H2O
Carbon dioxide turns lime water milky when passed through it because of formation of calcium carbonate. When carbon dioxide; so formed; is passed through lime water, lime water turns milky because of the formation of calcium carbonate.
CO2 + Ca(OH)2 ⇨ CaCO3 + H2O
On the electrolysis of brine, chlorine gas is deposited over anode which gives calcium oxychloride (Bleaching powder) on passing over slaked lime. The bleaching powder is used in disinfecting the drinking water.
Ca(OH)2 + Cl2 ⇨ CaOCl2 + H2O
Bleaching powder is used for disinfecting drinking water.
Therefore;
Metal carbonate ‘X’ is calcium carbonate.Solution ‘Y’ is lime water (Calcium hydroxide).Gas ‘G’ is chlorine gas.Dry ‘Y’ is dry calcium hydroxide (dry slaked lime).Compound ‘Z’ is bleaching powder (Calcium oxychloride).