Question

The exhausted anion-exchange resin is regenerated with

• A. dilute $NaOH$ solution
• B. dilute $NaCl$ solution
• C. dilute $HCl$ solution
• D. dilute $Na_{2}SO_{4}$ solution

Hint:

Cation Resins use Acids ($H^{+}$); Anion Resins use Bases ($OH^{-}$).

Answer 1

The Correct Option is A

Step 1: Concept
Ion-exchange resins must be regenerated once their active sites are occupied by ions from hard water.

Step 2: Meaning
Anion-exchange resins contain basic groups (like $-OH$) that exchange for anions in water. To reverse this, we need a source of hydroxide ions.

Step 3: Analysis
Passing dilute $NaOH$ through the exhausted resin replaces the captured anions with $OH^{-}$ ions, making the resin active again.

Step 4: Conclusion
Anion resins are regenerated with dilute $NaOH$ (Option A).
Final Answer: (A)