21. Which of the following does not show geometrical isomerism?
A
1, 2 - dichloro - 1 - pentene
B
1, 3 - dichloro - 2 - pentene
C
1, 1 - dichloro - 1 - pentene
D
1, 4 - dichloro - 2 - pentene
Answer :
1, 1 - dichloro - 1 - pentene
does not show22. Identify the compound that exhibits tautomerism :
A
2 - Butene
B
Lactic acid
C
2 - Pentanone
D
Phenol
Answer :
2 - Pentanone
23.
Which of the following compounds are meso forms ?
A
1 only
B
3 only
C
1 and 2
D
2 and 3
Answer :
3 only
24.
Which of the following is not a resonance form of the enolate ion formed in the following acid base equilibrium
A
B
C
D
Answer :
25.
Identify which of the strucutre below are meso structures ?
A
1 and 3
B
1, 3 and 5
C
1, 3 and 4
D
2 and 5
Answer :
1 and 3
26. Increasing order of stability among the three main conformations ( i.e. Eclipse, Anti, Gauche ) of 2 - fluoroethanol is
A
Eclipse, Anti, Gauche
B
Anti, Gauche, Eclipse
C
Eclipse, Gauche, Anti
D
Gauche, Eclipse, Anti
Answer :
Eclipse, Anti, Gauche
27.
The correct statement about the compounds $$A, B,$$ and $$C$$
A
$$A$$ and $$B$$ are identical
B
$$A$$ and $$B$$ are diastereomers
C
$$A$$ and $$C$$ are enantiomers
D
$$A$$ and $$B$$ are enantiomers
Answer :
$$A$$ and $$B$$ are enantiomers
28.
An optically active compound $$(A)$$ is treated with $$NaI$$ /acetone $$(B)$$ is obtained
What is true about $$(B)?$$
A
optically active
B
optically inactive and racemic form
C
optically inactive
D
None of these
Answer :
optically inactive and racemic form
leading to racemisation. 29. How many optically active stereoisomers are possible for butane - 2, 3 - diol?
A
1
B
2
C
3
D
4
Answer :
2
30.
The absolute configuration of
is :
A
$$\left( {2S,3S} \right)$$
B
$$\left( {2R,3R} \right)$$
C
$$\left( {2R,3S} \right)$$
D
$$\left( {2S,3R} \right)$$
Answer :
$$\left( {2S,3R} \right)$$
