Hydrogen Bonding in Water Molecules

Steps:

• Recall that a hydrogen bond forms between the partially positive hydrogen of one water molecule and the partially negative oxygen of another.
• Examine each diagram for a dashed line or notation indicating attraction between H of one H2O and O of another H2O.
• Eliminate diagrams showing covalent bonds (solid lines within molecules) or incorrect attractions like between two hydrogens.
• Select the diagram with the proper intermolecular dashed line between O-H...O.

Why A is correct:

• It depicts a dashed line between the hydrogen atom of one water molecule's O-H group and the oxygen atom of another, matching the definition of hydrogen bonding as a dipole-dipole interaction.

Why the others are wrong:

• B shows a covalent bond within a single molecule, not intermolecular.
• C illustrates attraction between two oxygen atoms, which does not occur in water.
• D depicts bonding between two hydrogen atoms, violating electronegativity rules.

Final answer: A