Question

In comparison to the zeolite process for the removal of permanent hardness, the synthetic resins method is :

• A. less efficient as the resins cannot be regenerated
• B. less efficient as it exchanges only anions
• C. more efficient as it can exchange only cations
• D. more efficient as it can exchange both cations as well as anions

Answer 1

The Correct Option is D

To understand why the synthetic resins method is more efficient compared to the zeolite process for the removal of permanent hardness, we need to look at how each process functions and what makes them different.

1. Zeolite Process:
   • The zeolite process is used for softening hard water by exchanging calcium (Ca²⁺) and magnesium (Mg²⁺) ions in the water with sodium (Na⁺) ions from the zeolite.
   • This method specifically targets cations that cause water hardness.
   • The exchanged zeolite can be regenerated by flushing it with a concentrated sodium chloride (salt) solution.
2. Synthetic Resins Method:
   • Synthetic resins are more advanced as they use ion-exchange resins which are capable of exchanging both cations and anions.
   • In this process, there are two types of resins used:
     • Cation Exchange Resin: These resins remove cations such as Ca²⁺ and Mg²⁺.
     • Anion Exchange Resin: These resins remove anions like sulfate (SO₄^2-) and chloride (Cl^-).
   • This dual ion-exchange capability means the synthetic resin method can handle a wider range of ions found in hard water, thus making it more efficient.
3. Conclusion:
   • Therefore, the synthetic resins method is considered more efficient because it can treat both cations and anions found in hard water, improving overall water quality by selectively removing a greater variety of ions contributing to hardness.

Thus, the correct answer is: more efficient as it can exchange both cations as well as anions.