Question

If $\alpha - D$ -glucose is dissolved in water and kept for a few hours, the major constituent(s) present in the solution is (are).
A) $\alpha - D$ -glucose
B) Mixture of $\beta - D$ -glucose and open chain D-glucose open chain D-glucose
C) Open chain D-glucose.
D) Mixture of $\alpha - D$ -glucose and $\beta - D$-glucose

Answer 1

Hint: We have to know that the basic functional unit of carbohydrates is \[C{H_2}O\]. It is a combination of carbon and water. The monomer unit of carbohydrate is \[C{H_2}O\]. Carbon and water are the basic units of carbohydrates. The word meaning of carbohydrate is \[{\text{carbon + hydrate}}\]. Hydrate means nothing but water. Carbohydrates are also known as saccharides. The word meaning of saccharides is sugar.

Complete answer:
We have to know that glucose is a well known and simplest example for carbohydrates. The chemical formula of glucose is \[{C_6}{H_{12}}{O_6}\]. The simplest representation of a glucose molecule is \[{(C{H_2}O)_6}\].
The glucose is one of the important substances in our body.
The structure of D-glucose is given below,

The solute of \[\alpha - D\] -glucose is dissolved in water and kept for few hours, the major constituent(s) present in the solution is (are) mixture of \[\alpha - D\]-glucose and $\beta - D$-glucose.
The chemical reaction for the above discussion given below,

According to the above discussion and reaction, we conclude the solute of \[\alpha - D\] -glucose is dissolved in water and kept for few hours, the major constituent(s) present in the solution is (are) mixture of \[\alpha - D\] -glucose and \[\beta - D\] -glucose.

Hence, option D is the correct answer.

Note:
We need to know that carbohydrates are classified as two types. This classification is based on the functional monomer in the carbohydrates. In carbohydrates aldehyde and ketone act as monomers. According to that, carbohydrates are separated as aldose and ketose.
carbohydrates are also classified as many types depending on the number of the carbon atom. Depending on the value of n \[(3,4,5,6,...)\]are classified as (trioses, tetroses, pentoses, hexoses etc…).
 Carbohydrates are classified as three major groups. This classification is based on the hydrolysis of carbohydrates. There are monosaccharides, oligosaccharides and polysaccharides. Monosaccharides here means only one carboxylic group in the molecule. Respect that carboxylic group hydrolysis will happen. Glucose, fructose are examples of monosaccharides. Lactose and maltose are examples of oligosaccharides, because they contain more than one functional monomer in the structure. Starch, glycogen and cellulose are the examples of polysaccharides because they have more than three monomers in the structure.