Q24 of 46 Page 1

Differentiate between the following:

(i) Amylose and amylopectin


(ii) Peptide linkage and glycosidic linkage


(iii) Fibrous proteins and globular proteins


OR


Write the chemical reactions to show that open structure of D-glucose contains the following:


(i) Straight chain


(ii) Five alcohol groups


(iii) Aldehyde as carbonyl group




Amylose


(i) Straight chain polymer


(ii) Test with iodine shows blue stains


(iii) 20% water soluble


Amylopectin


(i) Branched chain polymer


(ii) Iodine test shows re-brown stains.


(iii) 80-85% water solubility




(iv) has 1-4 glycosidic linkage


(iv) Has α -1,4 and α-1,6-glycosidic linkage.






Peptide linkage


(i) The proteins are linked by peptide bond.


(ii) It consists of ─CONH2─ bond between two molecules.


(iii) Hydrolysis of peptide bond gives two amino acids


Glycosidic linkage


(i) Monosaccharides are linked by glycosidic bond


(ii) The molecules are bonded by (─O─) link.


(iii) Hydrolysis gives two Monosaccharides.




Fibrous proteins


(i) Has linear poly-peptide chain arrangement


(ii) Insoluble in water, e.g. myosin


Globular proteins


(i) Coil arrangement of peptide chains.


(ii) Soluble n water, e.g. albumins, insulin




OR


D-glucose is obtained from hydrolysis or decomposition of sucrose by enzyme invertase. It has a straight chain, five alcohol groups and aldehyde as a carbonyl group as seen in the structure given below:



(i) the reaction of reduction of alcohol groups which results into hexane justifies the straight chain in the structure



(ii) Formation of penta-acetate when treatment with acetic anhydride suggests the presence of 5 alcohol groups.



(iii) Mild oxidation of glucose leads to formation of gluconic acid which can be detected using neutralisation in a basic medium.




More from this chapter

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22

An aromatic compound ‘A’, on heating with Br2 and KOH forms a compound ‘B’ of molecular formula C6H7N which on reacting with CHCl3 and alcoholic KOH produces a foul smelling compound ‘C’. Write the structures and IUPAC names of compounds A, B and C.

 23

Complete the following reactions:

(i)


(ii)


(iii)


OR


Write the chemical equations for the following reactions:


(i) Propanone is treated with dilute Ba(OH)2.


(ii) Acetophenone is treated with Zn(Hg)/conc. HCl


(iii) Benzoyl chloride is hydrogenated in presence of Pd/BaSO4


 25

E° for the given redox reaction is 2.71 V


Calculate Ecell for the reaction. Write the direction of flow of current when an external opposite potential applied is


(i) Less than 2.71 V and


(ii) Greater than 2.71 V


OR


(a) A steady current of 2 A was passed through two electrolytic cells X and Y connected in series containing electrolytes FeSO4 and FeSO4 until 2.8 g of Fe deposited at the cathode of cell X. how long did the current flow? Calculate the mass of Zn deposited at the cathode of cell Y.


(b) In the plot of molar conductivity (Λm) v/s square root of concentration (c1/2), following curve is obtained for two electrolytes A and B:



Answer the following:


(i) Predict the nature of electrolytes A and B


(ii) What happens on extrapolation of Λm to concentration approaching zero for electrolytes A and B?


 26

(a) How do you convert the following:

(i) Phenol to anisole


(ii) Ethanol to propan-2-ol


(b) write the mechanism of the following reaction:



(c) Why phenol undergoes electrophilic substitution more easily than benzene?


OR


(a) Account for the following:


(i) O-nitrophenol is more steam volatile than p-nitrophenol


(ii) T-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butylmethylether.


(b) Write the reaction involved in the following:


(i) Reamer-Tiemann reaction


(ii) Friedel-Crafts alkylation of phenol


(c) Give simple chemical test to distinguish between ethanol and phenol.