Bachelor of Science (B.Sc.) Sem V 2015 2016 2016 Chemistry 2 Question Paper - Mumbai University | munotes

Questions asked in this paper

• (2) Figures to the right indicate full marks

1. Q1 Answer any three of the following :—
   • (A) Complete the following reaction, name the reaction involved and suggesta 5
   • (B) (a) Give the mechanism involved in the formation of an acetal. 3
   • (b) Distinguish between nucleophilicity and basicity. 2
   • (C) What is Michael addition ? Give an and write its mechanism. 5
   • (D) Explain regioselectivity in elimination reaction with suitable examples. 5
   • (E) (a) Explain the mechanism involved in ihe following reaciton : 3
   • (b) Give a synthetic application of crossed Claisen condensation. 2
   • (F) (a) Whatis a thermodynamically controlled reaction ? Give any two examples. 3
   • (b) Explain the stereochemistry of Beckmann rearrangement. 2
2. Q2 Answer any three of the following
   • (A) Explain formation cf Mannich base and Hantzsch synthesis of pyridine. 5 What are such called ? Why ?
   • (B) Write synthesis of the following:— 5
   • (b) Chiral synthesis of ibuprofen
   • (C) Explain the use of microwaves in organic synthesis with any twoexamples. 5
   • (D) Give an account of electrophilic substitution reactions of furan. 5
   • (E) (a) Explain aromaticity of thiophene. 3
   • (b) Give Paal-Knorr synthesis of pyrrole. 2
   • (F) (a) Explain Hofmann exhaustive methylation followed by Hofmannelimination 3 using piperidine as the starting compond
   • (b) Write acid catalyzed ring opening reaction of furan. 2 ) Complete the following stat ments by choosing the correct answer from the 4 Addi tion of F r to 1, 3-butadiene gives product at — whether the following are true or false 4 Tertiary halides prefer to undergo reaction = (q) Electrophilicity is a kinetic property
   • (r) Sulphonation of naphthalene is kinetically controlled at high temperature
   • (s) In pinacol-pinacolone rearrangement, alkyl group migrates in preference Complete the following reactions. 4
   • (B) Match the columns appropriately :— 4
   • (p) Wanillin Hormone
   • (q) Bifenox I Antibiotic Answer any three of the following :—
   • (A) Discuss sourcewise classification of determinate errors with 5 of each class
   • (B) pH of the water sample was determined at different intervals. The results obtained were as follows
   • (ii) relative average deviation from mean in pph and ppt
   • (C) (a) Explain the terms: (i) bulk ratio (ii) size to ratio and give their 3 significance in sampling
   • (b) Define the terms : 2
   • (D) What is sampling ? Discuss the sampling of ieterogeneous liquids. 5
   • (E) Six samples of an iron ore were analysed for its iron content. The results 5 obtained were as follows: mg of iron | | 46-40 | 46:32 | | 46:39 Amount of iron was known to be 46:38 mg
   • (F) Describe different methods used for sampling of solids. 5
3. Q5 any three of the following :— 15 marks
   • (A) Explain the various niethods used to prevent reaction of AgCl precipitate with the titrant diving Volhard’s method of argentimetric titration
   • (B) What is neutralisation curve ? Sketch and explain the neutralisation curve for titration of weak acid against weak base
   • (C) With to UV-visible spectroscopy, explain the calibration curve method. the applications of UV-visible spectroscopy in qualitative
   • (D) Describe the construction and working of single beam spectrophotometer witti the help of a neat labelled diagram
   • (E) For base titration involving 10 cm? of with 0-1 M NaOH, Calculate the pH
   • (i) in the beginning of titration
   • (ii) after addition of 5 of NaOH
   • (iii) after addition of 10 cm’ of NaOH
   • (F) argentimetric titrations ? Discuss the use of adsorption indicators in detecting end point in argentimetric titrations, on of sample in a definite sequence at regular intervals is is collected with help of a errors whose cause cannot be located are called errors The errors in which absolute error is independent of sample size are q High precision is not the guarantee of high accuracy Precision represents reliability of the result sampling is sampling of air = Fluxes are used for decomposition of sampies
   • (a) Any acid-base titration essentially reaction
   • (b) The indicator used in Mohr’s is
   • (c) Prisms and gratings are _ in UV-visible
   • (B) State true or false : 3
   • (p) A photocathode is capable of emitting, electrons due to light incident on its surface
   • (q) Asingle beam spectrophotometer is advantageous than a double beam
   • (r) Eosin is as an indicator in acid base titration

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