Question

Choose the correct statement(s) related to conformers of n-Butane (about $C_2-C_3$ bond).

• A. Dipole moment of gauche conformer is non-zero
• B. Dipole moment of anti conformer is non-zero
• C. Dipole moment of gauche conformer is zero
• D. Dipole moment of anti conformer is zero

Answer 1

Answer: (C), (D)

Dipole moment of anti conformer is zero

Non-polar compounds have zero dipole moment.
In gauche conformer of n-Butane the methyl group are in similar direction.
In anti conformers of n-Butane the methyl groups are in opposite direction.
Generally, anti conformers have zero dipole moment and gauche conformer has non-zero dipole moment.

But in n-Butane, both gauche and anti form has zero dipole moment because the electronegativity difference is zero in case of alkanes so bond polarity is almost zero. Hence, alkanes are non-polar.

Therefore, all conformers of n-butane will have zero dipole moment and are non-polar.