Question

A chemical ‘A’ is used for the preparation of washing soda to recover ammonia. When $CO_{2}$ is bubbled through an aqueous solution of ‘A’, the solution turns milky. It is used in white washing due to disinfectant nature. what is the chemical formula of ‘A’?

• A. $Ca(HCO_{3})_{2}$
• B. CaO
• C. $Ca(OH)_{2}$
• D. $CaCO_{3}$

Answer 1

Answer: (C)

$Ca(OH)_{2}$

Answer 2

: $Ca(OH)_{2}$ is used in solvay process i.e., preparation of washing soda $(Na_{2}CO_{3}.10H_{2}O)$ to recover $NH_{3}$

$2NH_{4}Cl + \underset{'A'}{Ca(OH)_{2}} \rightarrow 2NH_{3} + CaCl_{2} + H_{2}O$

$Ca\underset{'A'}{(OH)_{2}} + CO_{2} \rightarrow \underset{Milkiness}{CaCO_{3}} \downarrow + H_{2}O$

$Ca(OH)_{2}$ is used in white washing due to its disinfectant nature.