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Conformational analysis of 1,2-dichloroethane

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Among the butane conformers, when viewed about C 2 -C 3 bond, which occur at energy minima on a graph of potential energy versus dihedral angle?

a: Gauche only Explanation

Explanation

b: anti Explanation

Explanation

c: syn Explanation

Explanation

d: Both gauche and syn Explanation

Explanation

The correct statement regarding conformation in butane is:

a: The two gauche forms, when viewed about C 2 - C 3 bond, are enantiomer Explanation

Explanation

b: There is greater barrier to rotation about C 1 — C 2 bond than to C 2 - C 3 bond Explanation

Explanation

c: Its gauche form has higher energy than an eclipsed form when CH 3 — and 'H' are eclipsing Explanation

Explanation

d: In the most stable conformer, dihedral angle between hydrogen atoms is only 90° Explanation

Explanation

Select the correct statement concerning conformers of ethane and hexachloroethane:

a: Both have different same number of important conformers Explanation

Explanation

b: Potential energy versus dihedral angle curves have similar nature in both cases Explanation

Explanation

c: Least stable conformer is hexachloroethane is most polar Explanation

Explanation

d: In potential energy versus dihedral angle diagram, there is greater difference between maxima and minima in ethane than in hexachloroethane Explanation

Explanation

Consider the potential energy diagram for rotation about the C2-C3 bond in pentane.The position marked A most likely corresponds to which of the following newmann projections.