Which orbital is non directional?
They are non directional because they are spherical in shape and probability of finding electrons at a particular distance from the nucleus is same in all directions.
Hydrogen bonding is a special type of dipole-dipole attraction between molecules. It results from the attractive force between a hydrogen atom(covalently bonded to a very E.N. atom such as a N, O, or F atom) and another very electronegative atom( N,O or F).
The factors for effective hydrogen bonding are: 1. Electronegativity of the atom must be high.2. Atomic size of the E.N. atom must be small. So, only F,O and N are able to make H-bond.
Intermolecular hydrogen bonding:
- Water (H₂O) 
- Alcohol (R-OH) and water (H₂O)
Intramolecular Hydrogen Bonding:
- o-nitrophenol