Enumerate the reactions of D-glucose which cannot be explained by its open chain structure.
Solution and Explanation
(1) Aldehydes give 2, 4-DNP test, Schiff's test, and react with NaHSO4to form the hydrogen sulphite addition product. However, glucose does not undergo these reactions.
(2) The pentaacetate of glucose does not react with hydroxylamine. This indicates that a free -CHO group is absent from glucose.
(3) Glucose exists in two crystalline forms - ∝andβ. The ∝-form (m.p. = 419 K) crystallises from a concentrated solution of glucose at 303 K and the β-form (m.p = 423 K) crystallises from a hot and saturated aqueous solution at 371 K. This behaviour cannot be explained by the open chain structure of glucose.
Top CBSE CLASS XII Chemistry Questions
- ${AgNO_3}$ does not decompose where :
- Azeotropic mixture of water and HCl boils at 381.5 K. By distilling the mixture it is possible to obtain
Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.
(i) (CH3 )2CHNH2 (ii) CH3 (CH2 )2NH2 (iii) CH3NHCH(CH3 )2
(iv) (CH3 )3CNH2 (v) C6H5NHCH3 (vi) (CH3CH2 )2NCH3 (vii) m–BrC6H4NH2
Give one chemical test to distinguish between the following pairs of compounds.
(i) Methylamine and dimethylamine
(ii) Secondary and tertiary amines
(iii) Ethylamine and aniline
(iv) Aniline and benzylamine
(v) Aniline and N-methylanilineAccount for the following:
(i) pKb of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
(iv) Although amino group is o– and p– directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v) Aniline does not undergo Friedel-Crafts reaction.
(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. (vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.
Top CBSE CLASS XII Biomolecules Questions
- What are monosaccharides?
- What are reducing sugars?
- Write two main functions of carbohydrates in plants.
- Classify the following into monosaccharides and disaccharides.
Ribose,2-deoxyribose,maltose, galactose,fructose and lactose. - What do you understand by the term glycosidic linkage?
Top CBSE CLASS XII Questions
- 2, b, c are in A.P. and the range of determinant $\begin{vmatrix}1&1&1\\ 2&b&c\\ 4&b^{2}&c^{2}\end{vmatrix}$ is [2, 16]. Then find range of c is
- A boy of mass 50 kg is standing at one end of a, boat of length 9 m and mass 400 kg. He runs to the other, end. The distance through which the centre of mass of the boat boy system moves is
- A capillary tube of radius r is dipped inside a large vessel of water. The mass of water raised above water level is M. If the radius of capillary is doubled, the mass of water inside capillary will be
- A circular disc is rotating about its own axis. An external opposing torque 0.02 Nm is applied on the disc by which it comes rest in 5 seconds. The initial angular momentum of disc is
- A circular disc is rotating about its own axis at uniform angular velocity \(\omega.\) The disc is subjected to uniform angular retardation by which its angular velocity is decreased to \(\frac {\omega}{2}\) during 120 rotations. The number of rotations further made by it before coming to rest is
Concepts Used:
Glucose
Glucose is a simple sugar, also known as dextrose, that is a primary source of energy for living organisms. It is a monosaccharide, meaning it consists of a single sugar unit, and is chemically classified as an aldohexose, which means it has six carbon atoms and an aldehyde functional group.
Glucose is produced by plants through the process of photosynthesis, where it is synthesized from carbon dioxide and water using energy from sunlight. It is also produced in the human body through the breakdown of complex carbohydrates, such as starch and glycogen, in the process of digestion.
Glucose is transported throughout the body via the bloodstream and taken up by cells where it is metabolized to produce energy in the form of ATP. Excess glucose can be stored in the liver and muscles as glycogen for later use.
Read Also: Structure of Glucose and Fructose
Glucose is an important component of many foods, such as fruits, honey, and sweetened beverages. It is also used as a sweetener in the food industry and as a medical treatment for hypoglycemia, a condition characterized by low blood glucose levels.
Measurement of glucose levels in the blood is an important diagnostic tool for monitoring and managing diabetes, a chronic metabolic disorder characterized by high blood glucose levels. Glucose testing can be done using a variety of methods, such as fingerstick testing and continuous glucose monitoring.