Which feature allows water to act as a universal solvent?

Water's ability to act as a universal solvent is primarily due to its polarity. Water molecules have a bent shape, with a partial negative charge near the oxygen atom and a partial positive charge near the hydrogen atoms. This polarity allows water to interact with various ions and polar substances, effectively surrounding and separating them into solution.

When ionic compounds like sodium chloride dissolve in water, the positive sodium ions are attracted to the negative end of the water molecules, while the negative chloride ions are attracted to the positive end. This interaction helps to pull the ions apart, allowing them to disperse throughout the solution. The polar character of water molecules means that they can solvate a wide variety of chemical substances, making water an excellent medium for biochemical reactions and processes.

In contrast, hydrogen bonds, while significant in affecting water's properties, are more about the interactions between water molecules than about its dissolving capabilities. Cohesion refers to the attraction between water molecules, and adhesion describes the attraction between water and other substances. Both cohesion and adhesion contribute to water's behavior in certain contexts, such as capillary action, but it is the polarity of water that fundamentally equips it with the ability to dissolve many different substances.