Question

What is the most common type of disaccharide?
A.\[{C_{10}}{H_{18}}{O_{19}}\]
B.\[{C_{10}}{H_{20}}{O_{10}}\]
C.\[{C_{11}}{H_{22}}{O_{11}}\]
D.\[{C_{12}}{H_{22}}{O_{11}}\]

Answer 1

Hint : Monosaccharide is a carbohydrate composed of simple elements carbon \[C\], hydrogen \[(H)\], and Oxygen\[(O)\]. Two monosaccharide molecules forms a bond that results in a disaccharide molecule. Some common example of the disaccharides are – sucrose, maltose, and lactose.

Complete Step By Step Answer:
To solve this question first we need to understand carbohydrates and composition of the disaccharides.
Carbohydrates are the naturally occurring compounds. These have four main categories – Monosaccharide, disaccharide, oligosaccharide and polysaccharide.
Carbohydrates are simple sugars and the disaccharides are known as “double sugars “because they are composed of two monosaccharide units joined by ether bonds. They have \[\alpha ,\beta \] - glycosidic linkage. And the hemi acetyl hydroxyl group resulted from the oxygen always participates in bond formation.
And the general formula for the disaccharides are\[{C_{12}}{H_{22}}{O_{11}}\].
Some common disaccharides are
\[sucrose = glu\cos e + fructose\]
\[Maltose = glu\cos e + glu\cos e\]
\[Lactose = glu\cos e + galactose\]
Let’s look at the structure of the maltose to understand its composition.
Maltose consists of two molecules of glucose joined by \[\alpha - 1,4 - \]glycoside linkage. During the bond formation water molecule is released.

In case of maltose only one hameactyl hydroxyl group participates in bond formation and the second one retains the properties of a reducing sugar.
Whereas, in case of sucrose, it is made of glucose and fructose, so both the hemi acetyl group is involved in bond formation thus the sucrose does not have reducing property.
Lactose is also a reducing sugar.

Hence, option D is correct.

Note :
It is to keep in mind that the non – reducing nature of some disaccharides such as sucrose and trehalose is advantageous also as they confer these double sugars stability. And the stability is the major criteria for the storage of the sugar, this is the reason why sucrose is also known as “table sugar”.