question_answer 1)

    In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question. (a) If both A and R are correct and R is the correct explanation of the A. (b) If both A and R are correct but R is not the correct explanation of the A. (c) If A is correct but R is incorrect. (d) If A is incorrect but R is correct. (A) Permanent hardness of water is removed by treatment with washing soda. (R) Washing soda reacts with soluble magnesium and calcium sulphate to form insoluble carbonates.

Answer:

  (a) Permanent hardness can be removed by treatment with washing soda. e.g., \[CaC{{l}_{2}}(aq)+N{{a}_{2}}C{{O}_{3}}(aq)\to \underset{(residue)}{\mathop{CaC{{O}_{3}}}}\,(s)+2NaCl(aq)\]