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Q99 (CAPF/2023) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Applied everyday chemistry

Pure, demineralized water, free from all soluble mineral salts is obtained by which of the following methods?

Result
Your answer: —  Â·  Correct: C
Explanation

Pure, demineralized water is obtained by removing essentially all inorganic salts through ion exchange processes [1]. This method involves passing water through a cation exchange resin bed, which replaces dissolved cations with hydrogen ions (H+), and an anion exchange resin bed, which replaces anions with hydroxyl ions (OH-). These ions then combine to form pure water (H2O). Unlike Calgon's method or simple boiling, which primarily address water hardness (calcium and magnesium ions) without removing all soluble salts, the dual-bed or mixed-bed ion exchange process targets the near-total removal of all ionic mineral contaminants [1]. While microfiltration removes particulate matter, it is generally insufficient for removing dissolved mineral salts. Consequently, the sequential use of cation and anion exchange resins is the standard industrial method for producing high-purity deionized water.

Sources

  1. [1] https://www.tn.gov/content/dam/tn/environment/water/ftc/references/study-guides/ftc_study-301_intro-wt-2.pdf
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SIMILAR QUESTIONS

NDA-II · 2010 · Q91 Relevance score: -2.54

When aqueous solutions of two salts are mixed, the third salt formed may appear as a solid precipitate or a clear solution depending upon the solubility of its ions. It is observed that all salts of Na, K, NH4 are soluble. All nitrates and bicarbonates are also soluble. All halides (chlorides, bromides, iodides) are soluble except those of Ag, Hg (I) and Pb. All sulphates are soluble except those of Ag, Ca, Ba and Pb. Which one among the following combinations of solutions will produce a solid precipitate?

NDA-II · 2018 · Q28 Relevance score: -4.52

Permanent hardness of water cannot be removed by which one of the following methods?

NDA-I · 2013 · Q41 Relevance score: -4.74

Which of the following statements regarding the property of hard water is/are correct? 1. Temporary hardness of water is due to the presence of soluble magnesium and calcium hydrogen carbonate. 2. Temporary hardness of water can be removed by boiling. 3. Calgon's method is applied to remove temporary hardness of water. 4. Permanent hardness of water is removed by Clark's method. Select the correct answer vising the code given below,