Why is water considered a universal solvent?

Water is considered a universal solvent primarily because it readily interacts with various solutes. This characteristic is due to its molecular structure and polarity. Water molecules are polar, having a partial positive charge on one side (the hydrogen atoms) and a partial negative charge on the other (the oxygen atom). This polarity allows water to surround and separate different solute molecules effectively.

When a substance is mixed with water, the positive end of the water molecules can interact with negatively charged ions, while the negative end can attract positively charged ions. This ability to solvate ionic and polar compounds makes water incredibly versatile in dissolving a wide range of substances, including salts, sugars, acids, and alcohols, which is why it is labeled as a universal solvent.

The other options do not effectively capture the essence of why water is termed a universal solvent. For example, stating that water can only dissolve solids overlooks its capability to dissolve liquids and gases as well. While water does have a high boiling point, this physical property does not directly relate to its solvent capabilities. The idea that water is less dense than air is also irrelevant in the context of solubility and does not help in understanding its role as a solvent.