Match List-I with List-II
|
List-I Sugar |
List-II Example |
|
(A). Invert Sugar |
(I). Lactose |
|
(B). Milk Sugar |
(II). Sucrose |
|
(C). Dextrose |
(III). Fructose |
|
(D). Ketohexose |
(IV). Glucose |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) - (II), (B) - (I), (C) - (IV), (D) - (III)
Many sugars are known by common names that come from their source, their optical rotation or their structure. Matching them needs the composition and properties of the main monosaccharides and disaccharides.
(A) Invert Sugar — This matches (II) Sucrose. Sucrose is dextrorotatory, but on hydrolysis it gives equal amounts of dextrorotatory glucose (+52.5°) and laevorotatory fructose (−92.4°). The laevorotation of fructose is larger, so the mixture is laevorotatory: the sign of rotation is inverted, and the product is called invert sugar.
\( \displaystyle \ce{C12H22O11} + \ce{H2O} \xrightarrow{\ce{H+}} \ce{C6H12O6}\,(\text{D-glucose}) + \ce{C6H12O6}\,(\text{D-fructose}) \)
(B) Milk Sugar — This matches (I) Lactose. Lactose is the disaccharide found in milk; it is made of β-D-galactose and β-D-glucose units.
(C) Dextrose — This matches (IV) Glucose. Natural glucose is D-(+)-glucose; it is dextrorotatory, which gives it the name dextrose.
(D) Ketohexose — This matches (III) Fructose. Fructose has six carbon atoms and a keto group at C-2, so it is a ketohexose (glucose, with an aldehyde group, is an aldohexose).
Shortcut: (A)-(II) appears only in Option (1).