Question

Explain why water is an excellent solvent.

Short answer

Water is an excellent solvent due to its unique properties, such as its polar nature, ability to form hydrogen bonds, and high dielectric constant. These characteristics allow water to dissolve a wide range of substances, including polar molecules, ionic compounds, and other substances that can form hydrogen bonds, making it the "universal solvent."

Step-by-step solution

Understand Solvent Properties

A solvent is a substance that can dissolve other substances, forming a solution. The ability of a substance to dissolve in a solvent depends on the solvent's polarity, ability to form hydrogen bonds, and the relative strength of the interactions between the solvent and solute molecules.

Recognize the Polar Nature of Water

Water is a polar molecule, meaning it has a partial positive charge on one end (the hydrogen atoms) and a partial negative charge on the other end (the oxygen atom). This occurs because the oxygen atom is more electronegative than the hydrogen atoms, resulting in an uneven distribution of electron density in the water molecule. The polar nature of water allows it to surround and dissolve other polar molecules and ionic compounds.

Understand Hydrogen Bonding in Water

Water can form strong hydrogen bonds with other molecules. A hydrogen bond is a type of electrostatic interaction that occurs between the partially positive hydrogen atom in a polar molecule (like water) and a partially negative atom (like oxygen, nitrogen, or fluorine) in another molecule. Because water can form hydrogen bonds, it can dissolve many substances that also engage in hydrogen bonding, like sugars and alcohols.

Consider Water's High Dielectric Constant

Water has a high dielectric constant, which is a measure of a substance's ability to reduce the electrostatic force between charged particles. This property makes it easier for water to dissolve ionic compounds, like salts, as it can effectively separate and stabilize the positively and negatively charged ions.

Review the Dissolving Process of Water

When a solute is added to water, the water molecules surround the solute particles. The oxygen atoms, with their partial negative charges, are attracted to the positive parts of the solute, while the hydrogen atoms, with their partial positive charges, are attracted to the negative parts of the solute. These attractions help to break the bonds between solute particles and form new bonds between the solute and water molecules, allowing the solute to dissolve.

Conclusion

Water's unique properties, including its polar nature, ability to form hydrogen bonds, and high dielectric constant, make it an excellent solvent. These properties allow water to dissolve a wide range of substances, like polar molecules, ionic compounds, and other substances that can form hydrogen bonds. This is why water is often referred to as the "universal solvent."