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JEE Main · 2026 · 08 Apr 2026 · Shift 2 · Biomolecules

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The incorrect statement from the following with respect to carbohydrates is :
  1. (A)All monosaccharides are reducing sugars.
  2. (B)The monosaccharide units obtained from hydrolysis of oligosaccharides are always the same.✓ Correct
  3. (C)Starch and cellulose are typical examples of polysaccharides, which are very high molecular weight compounds of more than ten monosaccharide units.
  4. (D)Open chain and cyclic structures co-exist at equilibrium that are responsible for certain properties as in the case of D-(+)-glucose.

Answer: (B)

Solution

On hydrolysis an oligosaccharide need not give identical monosaccharides: sucrose yields glucose and fructose, two different units, whereas maltose yields two glucose units, so the claim that the units obtained are always the same is false. The other statements hold: every monosaccharide has a free or potentially free carbonyl group and so is a reducing sugar; starch and cellulose are polysaccharides built from very many monosaccharide units; and glucose exists as an equilibrium between its open-chain and cyclic forms. The incorrect statement is the one asserting that the monosaccharide units from an oligosaccharide are always the same.

JEE Main · 2026 · 08 Apr 2026 · Shift 2 · Single correct option

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