Which of the following arrows correctly represents the net dipole moment of a water (H_2O) molecule?

• A. An arrow pointing from the oxygen atom toward the midpoint between the two hydrogen atoms.
• B. An arrow pointing from the midpoint between the two hydrogen atoms toward the oxygen atom.
• C. An arrow pointing from one hydrogen atom to the other hydrogen atom.
• D. No arrow, indicating that the molecule has no net dipole moment.

Answer: (A)

Verified step by step guidance

1. Understand that the dipole moment arrow points from the positive end to the negative end of a polar bond or molecule.
2. Recognize that in a water (H_2O) molecule, oxygen is more electronegative than hydrogen, so the O-H bonds are polar with partial negative charge on oxygen and partial positive charges on hydrogens.
3. Note the bent shape of the water molecule, which causes the individual bond dipoles to add up vectorially rather than cancel out.
4. Determine the net dipole moment direction by vector addition of the two O-H bond dipoles; this results in a dipole pointing from the midpoint between the two hydrogens toward the oxygen atom.
5. Conclude that the correct arrow representing the net dipole moment points from the midpoint between the two hydrogen atoms toward the oxygen atom.