The Total solution for NCERT class 6-12
Cation exchange resinshave large organic molecule with S03H group which are insoluble in water. Ion exchangeresin (RS03H) is changed to RNa on treatment with NaCl. Theresin exchange Na+ ions with Ca2+ and Mg2+ ions present in hard water and make it soft.2RNa(s) + M2+(aq) ——> R2M(s) + 2Na+(aq)where, M = Mg, Ca.The resins can be regenerated by adding aqueousNaCl solution.