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A polysaccharide X, on boiling with dilute H2SO4 at 393 K under 2-3 atm pressure, yields compound Y. Y on treatment with bromine water gives gluconic acid. X contains only beta-glycosidic linkages. Identify X.

1. Starch
2. Cellulose
3. Amylose
4. Amylopectin

Correct answer: Cellulose

Solution

Y + Br2/water gives gluconic acid, identifying Y as glucose. X is a glucose polymer. Among the options, only cellulose has exclusively beta-1,4-glycosidic linkages; starch, amylose, and amylopectin all have alpha-glycosidic linkages.

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