Alkanes (Conformations: Sawhorse and Newman Projections : Mechanism of Halogenation ) NEET Questions

Organic Chemistry - Hydrocarbons

Alkanes (Conformations: Sawhorse and Newman Projections : Mechanism of Halogenation ) MCQ Questions


13.
The number of possible conformations of ethane due to rotation about the C–C single bond is:
A.
Six
B.
Infinite
C.
Two
D.
Three
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ANSWER :
B. Infinite
14.
Which of the following statements is TRUE for the eclipsed conformation of ethane?
A.
It has maximum torsional strain and maximum energy
B.
It has maximum torsional strain and minimum energy
C.
It has minimum torsional strain and minimum energy
D.
It has minimum torsional strain and maximum energy
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ANSWER :
A. It has maximum torsional strain and maximum energy
15.
The bond angle and bond length in different conformations of ethane:
A.
Decrease in staggered form
B.
Change with rotation
C.
Remain unchanged
D.
Increase in eclipsed form
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ANSWER :
C. Remain unchanged
16.
Identify the conformation that is NOT a recognised extreme conformation of ethane:
A.
Skew (intermediate)
B.
Eclipsed
C.
Staggered
D.
Anti-periplanar
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ANSWER :
D. Anti-periplanar
17.
An intermediate conformation of ethane between eclipsed and staggered is called:
A.
Gauche
B.
Trans
C.
Skew
D.
Anti
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ANSWER :
C. Skew
18.
Why can the conformational isomers of ethane NOT be isolated at room temperature?
A.
They have identical structures
B.
The energy barrier between conformations (≈12.5 kJ mol⁻¹) is too small to be overcome at room temperature
C.
They have different molecular formulas
D.
They are optically active
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ANSWER :
B. The energy barrier between conformations (≈12.5 kJ mol⁻¹) is too small to be overcome at room temperature