Although anti conformation is more stable than the gauch conformation but in some cases gauch or skew conformation is more stable than the anti confirmation why?

Gauch or skew conformation is more stable than the anti because of the intramolecular hydrogen bonding which is geometrically possible only in the gauch conformation.

For examples:

Ethane-1,2-diol, 2-Fluoroethan-1-ol, 2-chloroethan-1-ol and 2-Aminoethanol etc.
2-chloroethane-1-ol:

Ethane-1,2-diol:

Realated Questions:

How many cyclic isomers possible of (C6H12) Hexene?

How many cyclic isomers possible of (C5H10) pentene?

Write the major and minor product of hydration of 1-Methylcyclopent-1-ene in acidic medium?

Why enol form of Beta Dicarbonyl compound more stable than those of monocarbonyl compounds?

Why enol form of phenol is more stable than its keto isomers?