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JEE Main · 2022 · 24 Jun 2022 · Shift 1 · Biomolecules

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A polysaccharide 'X' on boiling with dil H₂SO₄ at 393 K under 2-3 atm pressure yields 'Y'. 'Y' on treatment with bromine water gives gluconic acid. 'X' contains β-glycosidic linkages only. Compound 'X' is:
  1. (A)starch
  2. (B)cellulose✓ Correct
  3. (C)amylose
  4. (D)amylopectin

Answer: (B)

Solution

The polysaccharide X hydrolyzes to Y, which upon oxidation with bromine water gives gluconic acid, indicating Y is glucose. Since X contains only β-glycosidic linkages, it must be cellulose. Starch, amylose, and amylopectin all contain α-glycosidic linkages. Only cellulose has β(1→4) glycosidic linkages between glucose units.

JEE Main · 2022 · 24 Jun 2022 · Shift 1 · Single correct option

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