Which statement best describes hydrogen bonding in water?

Which statement best describes hydrogen bonding in water?

• A. Partial charges cause molecules to stack on each other
• B. Hydrogen bonds form between ionic species
• C. Hydrogen bonding is weaker than London dispersion
• D. Only nonpolar molecules form hydrogen bonds

Answer: (A)

Hydrogen bonding in water is driven by polarity. The oxygen in water is highly electronegative, pulling electron density toward itself in the O–H bonds, which gives the hydrogen a partial positive charge and the oxygen a partial negative charge. This setup allows an attraction between a hydrogen atom from one water molecule and the lone pairs on a neighboring water molecule’s oxygen. That electrostatic interaction is the hydrogen bond. This is captured by saying partial charges cause molecules to attract and orient themselves to form these bonds, creating the characteristic network in liquid water. Hydrogen bonds occur between polar covalent molecules, not between ions. They’re not weaker than London dispersion forces in the context of water; hydrogen bonds are typically stronger than dispersion interactions there. And hydrogen bonds don’t occur only in nonpolar molecules—nonpolar species generally lack the necessary partial charges, whereas water has the suitable O–H polarity to form these bonds.

Hydrogen bonding in water is driven by polarity. The oxygen in water is highly electronegative, pulling electron density toward itself in the O–H bonds, which gives the hydrogen a partial positive charge and the oxygen a partial negative charge. This setup allows an attraction between a hydrogen atom from one water molecule and the lone pairs on a neighboring water molecule’s oxygen. That electrostatic interaction is the hydrogen bond.

This is captured by saying partial charges cause molecules to attract and orient themselves to form these bonds, creating the characteristic network in liquid water. Hydrogen bonds occur between polar covalent molecules, not between ions. They’re not weaker than London dispersion forces in the context of water; hydrogen bonds are typically stronger than dispersion interactions there. And hydrogen bonds don’t occur only in nonpolar molecules—nonpolar species generally lack the necessary partial charges, whereas water has the suitable O–H polarity to form these bonds.