Question

Which of the following is true about conformers of 1, 2-dichloroethane?

• A. Its gauche form has higher potential energy than eclipsed conformer
• B. Anti form is more stable than gauche form
• C. Dipole moment of gauche form is non-zero
• D. Both (b) and (c)

Answer 1

The correct option is D Both (b) and (c)

Due to minimum tortional strain gauche form is more stable than the eclipsed conformer. Unstable conformer has higher potential energy. Thus, option (a) is wrong.

Gauche and anti form have minimum torsional strain but gauche form has more steric strain than anti form so anti form is the most stable conformer. Thus, option (b) is correct

In anti-form both the Cl groups are located in opposite direction so their individual dipole moment will cancel each other and the resultant dipole moment will be zero.

In gauche form, the Cl group are not located in exact opposite direction so their dipole moment will not get cancel. So, the resultant dipole moment is non-zero. Thus option (c) is correct.