Which statement best describes water as a solvent?

• A. Water is the universal solvent.
• B. Water is a poor solvent for ionic compounds.
• C. Water cannot dissolve polar compounds.
• D. Water only dissolves nonpolar substances.

Answer: (A)

Water’s ability to act as a solvent comes from its polarity and hydrogen-bonding capability. The molecule has a partial negative charge on oxygen and partial positive charges on the hydrogens, so it can surround and stabilize charged ions and polar molecules. Its high dielectric constant lowers electrostatic forces between ions, allowing salts to dissociate and become solvated by water molecules. This broad solvating power means water can dissolve many ionic and polar substances, which is why it’s often called the universal solvent. Of course, it doesn’t dissolve nonpolar substances well, and some compounds are not soluble in water. So the statement that water is the universal solvent best captures its wide dissolving ability, while the others contradict what water can do with ionic and polar compounds.