Which of the following statements are correct?
(A) Sucrose is a non-reducing sugar.
(B) Glucose is oxidised by bromine water.
(C) Glucose rotates plane-polarised light in the clockwise direction.
(D) Fructose is an aldohexose.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A), (B) and (C) only
(A) Sucrose is a non-reducing sugar. — True. In sucrose, C1 of α-D-glucose is joined to C2 of β-D-fructose, so the reducing groups of both units are used up in the glycosidic bond; no free aldehyde or ketone group is left.
(B) Glucose is oxidised by bromine water. — True. The mild oxidising agent bromine water oxidises the aldehyde group of glucose to –COOH, giving gluconic acid:
\( \displaystyle \ce{CHO-(CHOH)4-CH2OH} \xrightarrow{\ce{Br2\ water}} \ce{COOH-(CHOH)4-CH2OH} \)
(C) Glucose rotates plane-polarised light in the clockwise direction. — True. Glucose is D(+)-glucose; the (+) sign means dextrorotatory, and a dextrorotatory compound turns the plane of polarised light to the right, i.e. clockwise.
(D) Fructose is an aldohexose. — False. Fructose has a ketone group (at C2) and six carbon atoms, so it is a ketohexose; glucose is the aldohexose.
NCERT (2026-27 edition):
(A) 10.1.3 Disaccharides – “… These two monosaccharides are held together by a glycosidic linkage between C1 of α-D-glucose and C2 of β-D-fructose. Since the reducing groups of glucose and fructose are involved in glycosidic bond formation, sucrose is a non reducing sugar.”
(B) 10.1.2.1 Glucose – “4. Glucose gets oxidised to six carbon carboxylic acid (gluconic acid) on reaction with a mild oxidising agent like bromine water. This indicates that the carbonyl group is present as an aldehydic group.”
(C) 10.1.2.1 Glucose – “Glucose is correctly named as D(+)-glucose. ‘D’ before the name of glucose represents the configuration whereas ‘(+)’ represents dextrorotatory nature of the molecule.”
(C) (i) Optical activity – “… If the compound rotates the plane of plane polarised light to the right, i.e., clockwise direction, it is called dextrorotatory (Greek for right rotating) or the d-form and is indicated by placing a positive (+) sign before the degree of rotation.”
(D) 10.1.2.2 Fructose – “Fructose is an important ketohexose.”
(D) Structure of Fructose – “Fructose also has the molecular formula C6H12O6 and on the basis of its reactions it was found to contain a ketonic functional group at carbon number 2 and six carbons in straight chain as in the case of glucose.”