J & K CET Engineering J and K - CET Engineering Solved Paper-2003

  • question_answer
    Chemical A is used for water softening to remove temporary hardness. A reacts with sodium carbonate to generate caustic soda. When\[\text{C}{{\text{O}}_{\text{2}}}\] is bubbled through A, it turns cloudy. What is A?

    A) \[\text{CaC}{{\text{O}}_{3}}\]

    B) \[CaO\]

    C)  \[Ca{{(OH)}_{2}}\]

    D) \[Ca{{(HC{{O}_{3}})}_{3}}\]

    Correct Answer: C

    Solution :

     \[\underset{(A)}{\mathop{Ca{{(OH)}_{2}}}}\,+Ca{{(HC{{O}_{3}})}_{2}}\xrightarrow{{}}2CaC{{O}_{3}}\downarrow +{{H}_{2}}O\] Temporary hardness of water is removed by \[Ca{{(OH)}_{2}}.\]It converts bicarbonates into insoluble calcium and magnesium carbonate which are removed by filteration. \[\underset{(A)}{\mathop{Ca{{(OH)}_{2}}}}\,+\underset{\text{sodium}\,\text{carbonate}}{\mathop{N{{a}_{2}}C{{O}_{3}}}}\,\xrightarrow{{}}CaC{{O}_{3}}\] \[+\,\underset{\text{caustic}\,\text{soda}}{\mathop{2NaOH}}\,\] \[\underset{(A)}{\mathop{Ca{{(OH)}_{2}}}}\,+2C{{O}_{2}}\xrightarrow{{}}\underset{\begin{smallmatrix}  \text{calcium}\,\text{bicarbonate} \\  \,\,\,\,\,\,\,\,\,\,\,(cloudy) \end{smallmatrix}}{\mathop{Ca{{(HC{{O}_{3}})}_{2}}}}\,\]


You need to login to perform this action.
You will be redirected in 3 sec spinner