If a solid line represents a covalent bond and a dotted line represents intermolecular attraction, which of the choices shows a hydrogen bond? 1. H−H
2. H4C⋯H−F
3. H3N⋯H−O−H
4. H2O⋯H−CH3

3

Explanation:

Hydrogen bonding occurs between molecules in which hydrogen is bonded to a highly electronegative atom such as nitrogen, oxygen, chlorine, etc.

In option 3, the two compounds are H3N and H2O. In both molecules, hydrogen is directly attached to highly electro negative atoms(nitrogen and oxygen respectively). Hence, it is only in option 3 that we observe hydrogen bonding.

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explanation:

distance, luminosity, brightness, radius, chemical composition, and temperature