Which of the following is a polar molecule?

Water

The correct answer is option 1. Water.

Water \((H_2O)\) is a polar molecule because it has a bent molecular geometry and an unequal distribution of electrons, resulting in a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. This polarity allows water molecules to form hydrogen bonds with each other and with other polar molecules, giving rise to various unique properties such as high surface tension, cohesion, and adhesion.

The other options (1. Carbon tetrachloride, 2. Carbon dioxide, and 3. Benzene) are nonpolar molecules because they have symmetrical molecular structures and/or an equal distribution of charge, resulting in no overall dipole moment.