Question

how do water molecules orient themselves when sugar dissolves in water? both hydrogen and oxygen atoms face the sugar molecule. oxygen atoms face the sugar molecule. neither hydrogen nor oxygen atoms face the sugar molecule. hydrogen atoms face the sugar molecule.

Explanation:

Sugar (a polar molecule, e.g., sucrose) dissolves in water (a polar molecule) due to dipole - dipole interactions and hydrogen bonding. Water molecules are polar, with the oxygen atom being more electronegative (carrying a partial negative charge) and hydrogen atoms carrying partial positive charges. Sugar molecules have polar - OH groups (hydroxyl groups) or other polar regions. The partial negative charge on the oxygen atom of water is attracted to the positive regions of the sugar molecule, so the oxygen atoms of water molecules face the sugar molecule. The first option is incorrect as both can't face (due to charge distribution), the third is incorrect as there is an interaction, and the fourth is incorrect (hydrogen has partial positive, sugar's polar regions are not always negative to attract hydrogen in this orientation; oxygen's partial negative attracts sugar's positive regions).

Answer:

B. Oxygen atoms face the sugar molecule.