A solid compound 'x' on heating gives co2 gas and a residue. The residue mixed with water forms 'y'. On passing an excess of co2 through 'y' in water ,a clear solution 'z' is obtained. On boiling 'z' compound 'x' is reformed.the compound 'x' is..???
Options..a=na2co3
B=k2co3
C=can(hco3)2
D=caco3
Answers
Answer:
'x' = CaCO3(s)
'y' = Ca(OH)2 (l)
'z' = CaCO3(s)
So, x = CaCO3(s) is the correct answer.
Explanation:
A solid compound 'x' that is Calcium carbonate on heating gives Carbon dioxide gas and Calcium oxide as a residue.
CaCO3(s) ---∆----> CaO(s) + CO2(g)
The residue called Calcium oxide mixed with water forms 'y' that is Calcium hydroxide.
CaO(s) + H2O(l) ---------> Ca(OH)2 (l)
On passing an excess of Carbon dioxide gas through 'y' that is Calcium hydroxide in water ,a clear solution 'z' that is Calcium bicarbonate is obtained. When excess of Carbon dioxide is passed through the Calcium hydroxide, it becomes colourless due to the formation of Calcium bicarbonate because Calcium bicarbonate is soluble in water. If less amount of Carbon dioxide is passed through the Calcium hydroxide, it becomes milky due to the formation of Calcium carbonate because Calcium carbonate is a white precipitate which is insoluble in water.
Ca(OH)2 (l) + CO2(g) ------> Ca(HCO3)2 (l)
On boiling 'z' that is Calcium bicarbonate, compound 'x' is reformed.
Ca(HCO3)2 (l) ----∆-----> CaCO3(s) + H2O(l)
The compound 'x' that is Calcium carbonate.