Final answer:
Water has the ability to dissolve many substances due to its polar molecular structure and the resulting hydrogen bonding it forms with polar and ionic solutes. Ionic compounds dissolve in water through ion-dipole interactions, while polar substances dissolve by forming a hydration shell around the molecules. This solvation ability is key for life, enabling the transport of substances in the body and supporting ecosystems.
Step-by-step explanation:
Why Water Dissolves Many Substances
Water, known as the universal solvent, has a remarkable ability to dissolve a wide range of substances. This capability is largely due to the polar nature of water molecules. Each water molecule has a partial positive charge near the hydrogen atoms and a partial negative charge near the oxygen atom. This polarity allows water to engage in electrostatic interactions, particularly hydrogen bonding, with other polar or ionic substances.
Ionic compounds like table salt (sodium chloride) dissolve in water because water molecules surround the positively and negatively charged ions, dissociating them from each other.
This process, called dissolution, involves ion-dipole interactions, which are usually strong enough to overcome the ionic bonds within the solid compound. Consequently, these ions disperse uniformly in the water, becoming aqueous ions.
Polar molecules, such as sugar, are hydrophilic and dissolve in water due to the interaction of their polar bonds with water molecules. These substances have regions that carry a partial charge, leading to the formation of a hydration shell around the solute molecules. In contrast, nonpolar substances like oil and grease are hydrophobic and do not mix well with water because they lack the polar characteristics to form significant interactions with water molecules.
The exceptional solvation ability of water facilitates numerous biological and ecological processes vital to life. For example, in the human body, water carries nutrients and waste products between cells, and in the environment, it supports aquatic life by dissolving oxygen and other vital substances.
For a substance to be a true solution, such as a sugar-water mix, it should be stable without any dissolved particles settling out or being large enough to be removed by conventional filtering. Water's ability to form true solutions is yet another manifestation of its unparalleled role as a solvent.