North Maharashtra University 2009 B.Sc Chemistry Stereo-isomerism - Question Paper

S.Y.B.sc. Sem---II CH-222
*Stereo-isomerism*

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ques. for two marks.
1) select the accurate option of subsequent.
A) Optical activity is shown by a molecule which--------
1) contains atleast three asymmetric centres
2) is asymmetric or dissymetric as a whole.
3) has a plane of symmetry.
4) has a centre of symmetry.
B) The accurate order of stability is----------
1) chair form > boat form > twist boat form.
2) boat form > twist boat form > chair form.
3) chair form > twist boat form > boat form.
4) twist boat form > boat form > chair form.
C) An asymmetric carbon atom has------
1) 1 various atom or group.
2) 2 various atom or group.
3) 3 various atom or group.
4) 4 various atom or group.
D) The most unstable conformation of cyclohexane is-------
1) Chair 2) Half chair 3) Twist chair 4) Boat.
E) In the complete rotation of butane from 0o to 360o
the gauche conformation
appears-------
1) Once 2) Twice 3) Thrice 4) 4 times.
F) Which of subsequent is Z isomer?
1) H3C H 2) H3C Cl
C=C C=C
H COOH H Br
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3) CH3 Br 4) CH3 Cl
C=C C=C
H Cl Br H
G) In structural representation of molecule the prefixes Z & E stands for-------
1) Zigler—Erythro 2) Zusammen—Estrogen
3) Zeigler—Erhard 4) Zusammen—Entgegen.
H) Racemic mixture is eqimolar concentration ------
1) Enantiomers 2) Diastereomers
3) Enantiomer & meso compound 4) None of these
I) The priority sequence for the hydrogen isotopes is--------
1) H > D> T 2) T> D > H 3) H > T> D 4) D > T >H.
J) In the R-S notation, the prefixes R&S stands for -----
1) Rectus-simiantus 2) Rectus—sinister
3) Rotamer—simiantus 4) Rotamer—sinister.
K) ---------is the most stable conformation of n-butane.
1) Gauche 2) Fully eclipsed
3) Anti or staggered 4) Partially eclipsed.
L) Amongest the following, the Numan projection is--------
1) 2) 3) 4)
C–C
M) Which of the subsequent indicates G.I.-----
1) H3C H 2) Cl H
C=C C=C
H H H H
3) H H 4) H CH3
C=C C=C
CH3 CH3 H CH3
N) The atoms or groups which are behind the plane of the paper are shown by -------
1) Thick line 2) Normal lines
3) Dotted lines 4) Zig-zag lines
O) The prefixes used in the nomenclature of stereoisomer of oximes are------
1) Cis-trans 2) Z-E
3) Syn-anti 4) Eclipsed-Staggered.
2) describe or discuss the subsequent terms
a. Plane Polarised light and optical activity
b. Specific rotation and it’s formula

Earning:   Approval pending.