question_answer 62)

  When zeolite which is hydrated sodium aluminium silicate is treated with hard water, the sodium ions are exchanged with which of the ion(s)?      (a)\[{{H}^{+}}\]ions                        (b) \[M{{g}^{2+}}\] ions                                (c) \[C{{a}^{2+}}\]ions                   (d) \[SO_{4}^{2-}\] ions

Answer:

  (b, c)\[N{{a}_{2}}A\underset{Zeolite}{\mathop{{{l}_{2}}S{{i}_{2}}{{O}_{8}}}}\,\cdot x{{H}_{2}}O+C{{a}^{2+}}\to \] \[CaA{{l}_{2}}S{{i}_{2}}{{O}_{8}}\cdot x{{H}_{2}}O+2N{{a}^{+}}\] or \[M{{g}^{2+}}\to MgA{{l}_{2}}S{{i}_{2}}{{O}_{8}}\cdot x{{H}_{2}}O+2N{{a}^{+}}\]