Final answer:
Water is polar due to the unequal sharing of electrons between oxygen and hydrogen atoms, resulting in a bent shape with a separation of charge. This causes the molecule to have a net dipole, allowing it to form hydrogen bonds and effectively dissolve other polar substances.
Step-by-step explanation:
Water is a polar molecule because it has a bent molecular structure, which occurs due to the two lone pairs and two hydrogen atoms bonded to the oxygen atom. In a water (H₂O) molecule, the oxygen atom, which contains eight protons, is more electronegative and attracts the shared electrons more than the hydrogen atoms, which contain only one proton each. This unequal sharing of electrons leads to a net separation of positive and negative charges, forming a dipole with a slightly negative charge on the oxygen and a slightly positive charge on the hydrogens. This asymmetrical charge distribution gives water its polar characteristics, allowing it to attract other polar molecules and establishing hydrogen bonds between water molecules.
The bent shape of the water molecule means that the individual O-H bond dipoles do not cancel each other, and the molecule has a net dipole that contributes to its polar nature. The separation of charge within the water molecule results in the oxygen end being slightly negative while the hydrogen side is slightly positive, leading to the attraction of opposite charges between molecules, and making water an excellent solvent for other polar substances.