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Biomolecules question

2021 · 27 Jul · Shift 1 · Q8
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Biomolecules question

2021 · 27 Jul · Shift 1 · Q8

JEE MainChemistryBiomoleculesMCQ+4 / −1
Which one among the following chemical tests is used to distinguish monosaccharide from disaccharide?
  1. A
    Seliwanoff's test
  2. B
    Iodine test
  3. C
    Barfoed test
  4. D
    Tollen's test
View written solutionFree

Correct answer: C

  1. Goal: We need a test that distinguishes a monosaccharide from a disaccharide.

  2. Check each option:

    A. Seliwanoff's test
    This test distinguishes ketoses from aldoses.
    So it is not specifically used to distinguish monosaccharides from disaccharides.

    B. Iodine test
    This test is mainly used for starch (gives blue color with starch).
    It does not distinguish monosaccharides from disaccharides.

    C. Barfoed test
    Barfoed's reagent distinguishes monosaccharides from disaccharides based on their reducing ability in acidic medium.

    • Monosaccharides reduce Barfoed's reagent rapidly, giving a red precipitate of cuprous oxide.
    • Disaccharides react much more slowly or not within the test time.
      Therefore, this is the correct test.

    D. Tollen's test
    Tollen's reagent is used to detect reducing sugars/aldehydes. Both many monosaccharides and some disaccharides can give this test.
    Hence it does not specifically distinguish monosaccharides from disaccharides.

  3. Conclusion:
    The correct answer is Barfoed test.

Option C\boxed{\text{Option C}}Option C​

  1. Comparison with stored correct answer:
    Stored correct answer = C
    Derived answer = C
    Hence, they agree.
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