Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
+1 vote
21.4k views
in Chemistry by (30.0k points)

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

Please log in or register to answer this question.

1 Answer

+2 votes
by (130k points)

The process of treating permanent hardness of water using synthetic resins is based on the exchange of cations (e.g., Na+, Ca2+, Mg2+ etc) and anions (e.g., Cl , SO4 2– , HCO3 etc) present in water by H+ and OH ions respectively. 

Synthetic resins are of two types: 

1) Cation exchange resins 

2) Anion exchange resins 

Cation exchange resins are large organic molecules that contain the –SO3H group. The resin is firstly changed to RNa (from RSO3H) by treating it with NaCl. This resin then exchanges Na+ ions with Ca2+ and Mg2+ ions, thereby making the water soft. 

There are cation exchange resins in H+ form. The resins exchange H+ ions for Na+, Ca2+, and Mg2+ ions. 

Anion exchange resins exchange OH ions for anions like Cl HCO3- , , and SO4 2– present in water. 

During the complete process, water first passes through the cation exchange process. The water obtained after this process is free from mineral cations and is acidic in nature. This acidic water is then passed through the anion exchange process where OH ions neutralize the H+ ions and de-ionize the water obtained. 

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...