Question

Chemical A is used for water softening to remove temporary hardness, A reacts with Na2Co3 to generate caustic soda. When CO2 is bubbled through A, it turns cloudy. If the chemical formula of A is $Ca (OH)_{2} + CO_{2} \rightarrow CaCo_{?} \downarrow + H_{2}O$ then what is the value of ?

Answer 1

Explanation:
The chemical A is calcium hydroxide (Ca(OH)2). It is used for water softening to remove temporary hardness. It reacts with sodium carbonate to form caustic soda.Na2CO3+Ca(OH)2→CaCO3↓+NaOHWith carbon dioxide gas, it forms calcium carbonate which turns lime water milky.Ca(OH)2+CO2→CaCO3↓+H2O Hence, the correct answer is 3.