9.23. Discuss the principle and method of softening of hard water by synthetic ion-exchange resins.

<p><strong>9.23.&nbsp;</strong>Cation exchange resins have large organic molecule with SO₃H group which are insoluble in water. Ion exchange resin (RSO₃H) is changed to RNa on treatment with NaCl. The resin exchange Na⁺ ions with Ca²⁺&nbsp;and Mg²⁺&nbsp;ions present in hard water and make it soft.<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 2RNa (s) + M²⁺ (aq) ——&gt; R₂M (s) + 2Na⁺ (aq)<br>where, M = Mg, Ca.<br>The resins can be regenerated by adding aqueous NaCl solution.</p>

0 Upvotes 0 Upvotes 0 Downvotes

• • Report Abuse
• Comment