Final answer:
Water molecules have a polarity due to the electronegativity difference between oxygen and hydrogen atoms. This polarity allows water to form hydrogen bonds and act as a solvent for polar and ionic substances. Water's cohesion and adhesion properties are also influenced by its polarity.
Step-by-step explanation:
Water molecules have a polarity due to an uneven distribution of charge caused by the electronegativity difference between oxygen and hydrogen atoms. The oxygen atom attracts electrons more strongly, resulting in a partial negative charge, while the hydrogen atoms have a partial positive charge.
Water's polarity allows it to form hydrogen bonds with other polar molecules or ions. This ability to attract and bond with other substances makes water an excellent solvent. For example, water can dissolve ionic compounds like table salt (sodium chloride) because the water molecules surround and separate the individual ions. Additionally, water's polarity contributes to its cohesive and adhesive properties.