question_answer 57)

  A chemical ?A? is used for the preparation of washing soda to recover ammonia. When \[C{{O}_{2}}\] is bubbled through an aqueous solution turns milky. It is used in white washing due to disinfectant nature. What is the chemical formula of ?A?? (a) \[Ca{{(HC{{O}_{3}})}_{2}}\]                   (b) \[CaO\]                         (c) \[Ca{{(OH)}_{2}}\]                     (d) \[CaC{{O}_{3}}\]

Answer:

  (c) \[\underset{(A)}{\mathop{Ca{{(OH)}_{2}}}}\,+2N{{H}_{4}}Cl\to 2N{{H}_{3}}+CaC{{l}_{2}}+2{{H}_{2}}O\] \[\underset{\underset{\underset{Used\,in\,white\,washing}{\mathop{\downarrow }}\,}{\mathop{(A)}}\,}{\mathop{Ca{{(OH)}_{2}}}}\,+C{{O}_{2}}\to \underset{Milky\,\text{soln}.}{\mathop{CaC{{O}_{3}}}}\,+{{H}_{2}}O\]