Read the following statements carefully regarding the conformational isomers of different organic compounds: I. The gauche conformation of 2 -fluoroethanol is more stable than its anti conformation. II. The dihedral angle between the two methyl groups in the most stable conformer of n -butane is 180^ . III. The gauche conformer of 1,2-dichloroethane has a net zero dipole moment ( =0 ). IV. Torsional strain is maximum

Step-by-step solution

Statement I is correct. In 2-fluoroethanol, the gauche conformation is more stable than the anti conformation due to intramolecular hydrogen bonding between the highly electronegative fluorine atom and the hydrogen atom of the hydroxyl group. Statement II is correct. The most stable conformer of n -butane is the anti conformer, where the bulky methyl groups are placed as far apart as possible to minimize steric repulsion. The dihedral angle between the two methyl groups in this conformation is 180^ . Statement III