B.Pharm. (Semester IV) (New CBCS) Examination, 2018
organic chemistry iii
Day and Date Friday, 11-5-2018 Max. Marks 70
Time 3.00 p.m. to 6.00 p.m.
Multiple choice questions
I. Choose the most appropriate one from the following answers (1×15=15)
Stability order of Carbo-cations is as follows
Allylic 2° Methyl Allylic 3° 1°
Allylic Methyl 2° 3° Allylic 1°
Curtius rearrangement reaction yields
Alkene 1° Amine
2° Amine 3° Amine
Claisen rearrangement leads to products with substitution at positions
Ortho Para
Meta Both ortho and para
The catalysts used in pericyclic reactions are
AlCl3 TiCl4
SnCl4 None
The term syn-periplanar means
±30° same side ±60° same side
±150° opposite side None
P
SeatNo.Set
SLR-TA 27 *SLRTA27*
Set P
Products obtained in pericyclic reaction with light and heat as energy source are
Same Different
Unaffected NA
A substance has configuration if, order of ranked groups arranged is
Clockwise Anti-Clockwise
Planar None
If a reaction with a specific reactant produces a specific product, it is
Stereoselective Partially stereoselective
Stereospecific Partially stereospecific
isomers are generated by different oreintation of groups on a ring.
Geometric Conformational
Compositional None
10) Steric repulsion means, repulsion in a molecule due to
Electrons Size of a group
Orientation of a group charge
11) Acetone and propanol are examples for
Geometric isomers Stereoisomers
Conformers Tautomers
12) Choose correct reagent for completing the following reaction
R1CRClCH2R2 R1 CR CH R2
HCl, H2O NaOH
NaOET H2O
13) In reactions undergoing elimination according to Saytzeff mechanism, alkene formed is
Unsubstituted Less substituted
Most substituted Equally substituted
*SLRTA27* SLR-TA 27
Set P
14) representation of a conformer gives us an angled, 3D look.
Fischer Saw-horse
Line-Wedge-Dash Newmann
15) and neopentane are examples for structural isomers.
Isopentane 1-Chloropentane
2-pentanol 3-Pentanone
II. Answer any five questions of the following (5×5
How are isomers classified Why we need to study isomerism
What is Stereospecificity Write a note on E1 reactions.
Describe in brief about Configuration and Conformation.
What are electrophilic rearrangement reactions Write a brief note on Favorskii rearrangement.
Explain electrocyclic reaction with an example.
Write a note on the stereochemistry of SN2 and E2 reactions.
III. Answer any three questions of the following (10×3=30)
How do you separate enantiomers from a racemic mixture Explain with examples.
Discuss briefly about different electrophilic addition reactions. Add a note on the stereochemistry of these.
Discuss about
Bayer-Villiger oxidation
Fries rearrangement reaction.
How do you name geometrical isomers Explain with examples.
Write a note on the conformational changes in Butane with changes in its potential energy.