Hydrogen And Its Compounds Question 217
Question: Chemical (A) is used for water softening to remove temporary hardness. (A) reacts with sodium carbonate to generate caustic soda. When $ CO_2 $ is bubbled through a solution of (A), it truns cloudy. What is the chemical formula of (A)-
Options:
A) $ CaCO_3 $
B) $ CaO $
C) $ Ca{{(OH)}_2} $
D) $ Ca{{(HCO_3)}_2} $
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Answer:
Correct Answer: C
Solution:
[c] Lime water $ [Ca{{(OH)}_2}] $ is used to remove the temporary hardness of water. $ [Ca{{(OH)}_2}] $ reacts with bicarbonates of Ca to form insoluble carbonate. $ Ca(HCO_3)(aq)+Ca{{(OH)}_2}\to 2CaCO_3\downarrow +2H_2O $
$ Ca{{(OH)}_2}+Na_2CO_3\to NaOH+CaCO_3 $
$ Ca{{(OH)}_2}+CO_2\to CaCO_3+H_2O $
BETA
