BSc Sem VI 2022 2023 Apr 2023 CHEMISTRY III ORGANIC CHEMISTRY Question Paper - Mumbai University | munotes

Questions asked in this paper

• Please check whether you have got the right question paper

1. Q2 Figures to right indicates full marks
2. Q1 Answer ANY FOUR of the following: A Discuss whether the addition of bromine to 2-butene is stereospecific or stereoselective. 5 B Explain the mechanism and stereochemistry of Sni reactions using suitable example. 5 C Write a note on enantiotopic ligands. 3
   • b) Explain the term: Prochiral centre 2 D Explain the stereochemistry of KMnO, oxidation of maleic acid and fumaric acid. 5 E What are a-amino acids? How are they classified? 3
   • b) Give preparation of alanine by Strecker synthesis. 2 F Explain stepwise synthesis of a tripeptide using Merrifield’s solid phase synthesis method. 5 Give two advantages of this method of synthesis Answer ANY FOUR of the following: A Complete the following reaction, identify it and explain its mechanism: 5 B What is Michael reaction? Explain the mechanism of the reaction. Identify the intermediate. 5 C Give reactions for the following:
   • a) Conversion of D-Glucose into D-Arabinose 3
   • b) Action of conc. on D-Glucose and D-Fructose 2 Write stepwise reactions to show the action of phenylhydrazine on D- Fructose? 3
   • b) Explain the phenomenon of mutarotation in Glucose. 2 Draw the Fischer projection of D- Fructose and convert to Haworth formula 3
   • b) What are epimers? Draw the structure of anyone epimer of D-Glucose. 2 F Draw structures for the following: 5
   • i) Enantiomer of D-Glucose li) Open chain structure of Aldotriose ili) Product formed by action NaBH, on D-Glucose Iv) Chair conformation of B-D-Glucopyranose
   • v) Diastereomer of D-Glucose
3. Q3 Answer ANY FOUR of the following: A Explain the following terms: 5
   • ii) Types of bending vibrations Explain how inductive effect plays an important role in deciding the value of chemical shift 3 with a simple example?
   • b) Why TMS is used as a standard in PMR spectroscopy? 2 the structure of pyrimidine bases present in DNA? 3 D Explain the primary structure of nucleic acids? 5 E An organic compound has the molecular formula M.F: Determine the index of its 5 hydrogen deficiency and deduce its structural formula from the following spectral data? PMR Spectrum: (in 6 ppm): 1.6(3H,d) , s,D2O exchangeable) , 4.9 (1H,q) , 7.4 Suggest a structure for the compound and justify your answer F An organic compound has the molecular formula M.F Determine the index of its 5 hydrogen deficiency and suggest a structure for the compound. Justify your answer?
4. Q4 Answer ANY FOUR of the following: A Complete the following reactions 5
   • ii) Ni+ iv)
   • v) Raney Ni + H2 B is Lindlar’s catalyst? Explain its use in partial reduction of alkynes and its selectivity? 3
   • b) Complete the following reactions: 2 C a) Howare polymers classified on the basis of properties of polymers? 3
   • b) Give the preparation and uses of Nylon 6,6? 2 Explain the following terms with examples 3
   • b) Write the synthesis of Buna —S rubber. 2
   • b) Explain the allylic and benzylic bromination using NBS 2 F Draw the structure and give one use of the following polymers- 3
   • b) Write the structure and use of Ziegler Natta catalyst. 2 State whether the following are true or false: (any five) 5
   • a) The two faces in ethyl methyl ketone are homotopic in nature
   • b) E, elimination reaction requires antiperiplanar geometry of the two leaving groups of
   • c) Epoxide contains a three membered heterocyclic ring with one oxygen atom present in the
   • d) All stereospecific reactions are not stereoselective in nature
   • e) The reactions where only one diastereomer of all the possible diastereomers of the product is formed, are known as diastereoselective reactions
   • f) A dipeptide is formed from two a-amino acids
   • g) K-phthalimide is used as one of the reactants in Gabriel’s synthesis of acids
   • h) Proteins are formed by ester linkages between different a-amino acids Choose the most correct option to answer the following (ANY FIVE): 5
   • a) What is the intermediate formed in Pinacol-Pinacolone rearrangement?
   • b) What is the base catalysed rearrangement of o-haloketones to carboxylic acid derivatives
   • c) Which of the following is an aldotetrose?
   • d) Identify the anomer of a-D-Fructofuranose
   • i) iii) B-D-Glucopyranose
   • e) Identify the product/s formed on treating D-Fructose with H2/Ni
   • f) How many moles of periodic acid are required per mole of D-Fructose?
   • i) 3 iii) 5
   • ii) 4 iv) 6
   • g) Identify the oligosaccharide
   • i) Starch Ribose the blanks: ( Any five) 5
   • a) A sharp absorption band due to >C=O stretching in ketones appears in the region around
   • b) Nujol is
   • c) The position of the signals in NMR represents the ------ of the protons
   • d) NMR is based on the property of
   • e) scale the position of TMS signal is taken as ------------- ppm
   • f) The sugar component in DNA is
   • g) Uracil is a derivative of
   • h) A-T and C-G are called ---------- base pairs State whether the following are True or False: (any five) 5
   • b) Lithium Aluminum hydride (LAH) is mild reducing agent
   • c) In isotactic polymer all the side chains are arranged on the same side of the polymeric
   • d) Polycarbonates are used in bike helmets
   • e) is Wilkinson’s catalyst
   • f) oxidises only active methyl or methylene group without affecting carbonyl group
   • g) acrylate can be used as artificial skin

Read from the scan above, so a character or two may differ. The scan is the original.