Increasing order of stability among the three main configurations (i.e., eclipsed, Anti, Gauche) of 2- fluoroethanol is

→ Gauche conformation is highly stable due to chelation or intramolecular hydrogen bonding.→ Staggered conformation is more stable compared to eclipsed conformation,due to low torsional strain.TORSIONAL STRAIN: The repulsions between the front carbon C—H bonded electrons and back carbon C—H bonded electrons causes the strain in the molecule,such repulsions are more in eclipsed conformation.This strain leads to the unstability in the conformation.The strain in the molecule due to the electronic repulsions is said to be torsional strain.