Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Sucrose is a disaccharide and a non-reducing sugar.
Reason (R): Sucrose involves glycosidic linkage between of -glucose and of -fructose.
Choose the most appropriate answer from the options given below:
Assertion (A): Sucrose is a disaccharide and a non-reducing sugar.
Reason (R): Sucrose involves glycosidic linkage between of -glucose and of -fructose.
Choose the most appropriate answer from the options given below:
- (A)Both (A) and (R) are true but (R) is the true explanation of (A).
- (B)(A) is true but (R) is false.✓ Correct
- (C)(A) is false but (R) is true.
- (D)Both (A) and (R) are true but (R) is not the true explanation of (A).
Answer: (B)
Solution
Sucrose is built from one glucose and one fructose unit, so it is a disaccharide, and the glycosidic bond ties up the anomeric carbon of both units, leaving no free hemiacetal or hemiketal group; it gives no response to Tollens' or Fehling's reagent and is non-reducing, so the assertion is true. The linkage, however, runs from of -glucose to of -fructose, the reverse of what is stated, so the reason is false. The assertion is true but the reason is false.
JEE Main · 2021 · 26 Aug 2021 · Shift 2 · Single correct option