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प्रश्न
Enlist the properties of glucose that can not be explained on the basis of open chain structure of it
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उत्तर
Although the open chain structure of D (+) − Glucose explains most of its reactions, it fails to explain the following facts:
a) D (+)-Glucose does not undergo certain characteristic reactions of aldehydes
eg., Glucose does not form NaHSO3 addition product, aldehyde-ammonia adduct 2, 4 − DNP derivative and does not respond to Schiff’s reagent test.
b) Glucose reacts with NH2OH to form an oxime but glucose pentaacetate does not react
with NH2OH, which implies that the free aldehyde group is absent in glucose pentaacetate
c) D(+)-Glucose exists in two stereoisomeric crystalline forms, i.e. α-glucose and
β-glucose, called anomers. α-D(+)-Glucose is obtained when a concentrated aqueous or
alcoholic solution is crystallised at 303 K. It has a melting point of 419 K and has a
specific rotation of +111° in a freshly prepared aqueous solution.
However, when glucose is crystallised from water above 371 K, β-D(+)-glucose is
obtained. It has a melting point of 423 K and has a specific rotation of +19.2° in a
freshly prepared aqueous solution. This behaviour could not be explained by the open
chain structure of glucose.
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संबंधित प्रश्न
Maltose is a
(a) Polysaccharide
(b) Disaccharide
(c) Trisaccharide
(d) Monosaccharide
Write the product when D-glucose reacts with conc. HNO3.
Glucose on reaction with HI gives n-hexane. What does it suggest about the structure of glucose?
Differentiable between the following:
Amylose and Amylopectin
What do you observe when glucose is treated with bromine water?
Answer the following question.
What is the basic structural difference between glucose and fructose?
Choose the appropriate answer(s) for the below representation from the options given
What is the most abundant organic compound on earth?
Oxime is formed by treating glucose with ____________.
Acetylation of glucose yields ____________.
Glucose does not give Schiff’s test because of the formation of cyclic ____________.
Which of the following statements is incorrect regarding glucose?
Which one of the following compounds is different from the rest?
When glucose reacts with bromine water, the main product is ____________.
Reduction of glucose by HI suggest that ____________.
A solution of D-glucose in water rotates the plane polarised light ____________.
The number of chiral carbon atoms present in cyclic structure α-D(+) glucose:
The number of chiral carbons in ß-D(+) glucose is ____________.
Three structures are given below in which two glucose units are linked. Which of these linkages between glucose units are between C1 and C4 and which linkages are between C1 and C6?
| (I) |  |
| (II) |  |
| (III) |  |
Write the reactions of D-glucose which can’t be explained by its open-chain structure. How can cyclic structure of glucose explain these reactions?
On the basis of which evidences D-glucose was assigned the following structure?
\[\begin{array}{cc}
\ce{CHO}\\
|\phantom{....}\\
\phantom{..}\ce{(CHOH)4}\\
|\phantom{....}\\
\phantom{..}\ce{CH2OH}
\end{array}\]
Consider the following reactions:
(i) \[\ce{Glucose + R-OH ->[Conc. HNO3] [A] ->[X eq of][(CH3CO)2O] Acetyl derivative}\]
(ii) \[\ce{Glucose ->[Ni/H2] [A] ->[Y eq of][(CH3CO)2O] Acetyl derivative}\]
(iii) \[\ce{Glucose ->[Z eq of][(CH3CO)2O] Acetyl derivative}\]
'X, 'Y' and 'Z' in these reactions are respectively:
The number of asymmetric carbon atoms in the glucose molecule in open and cyclic form is ______.
Give the reaction of glucose with hydrogen cyanide. Presence of which group is confirmed by this reaction?
