Final answer:
Water is a polar molecule due to polar covalent bonds between hydrogen and oxygen, where hydrogen has a partial positive charge and oxygen has a partial negative charge. This polarity allows for hydrogen bonding with other polar molecules, resulting in hydrophilic interactions.
Step-by-step explanation:
Water is a polar molecule, crucial for life due to its unique properties. The hydrogen and oxygen atoms within water molecules form polar covalent bonds. Electrons in these bonds are unevenly distributed because oxygen is more electronegative than hydrogen, attracting shared electrons more. Consequently, the hydrogen atoms have a partial positive charge (δ+), and the oxygen atom has a partial negative charge (δ-). The molecule's bent structure, with a H-O-H bond angle of approximately 105°, contributes to its polarity, as the dipoles point towards the oxygen and do not cancel each other out. This separation of charge allows water molecules to attract each other and other polar substances through hydrogen bonding, leading to hydrophilic interactions, such as the solubility of sugars in water.
Contrastingly, substances without these polar properties, like oils and fats, do not readily form hydrogen bonds with water and hence are classified as hydrophobic ('water-fearing'). The capacity of water molecules to engage in hydrogen bonding is crucial for many biological processes and the behavior of substances in aqueous solutions.