What is the universal solvent?

• A. Salt
• B. Alcohol
• C. Water
• D. Oil

Answer: (C)

Water is able to dissolve a wide range of substances because of its polarity and ability to form hydrogen bonds. The molecule has a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom, so it can interact with charged ions and with polar molecules. When a salt dissolves, water molecules surround the individual ions with their positive ends facing anions and their negative ends facing cations, creating hydration shells that separate and stabilize the ions in solution. This ion-dipole interaction and hydration capability let water dissolve many ionic and polar substances, which is why it’s called the universal solvent.

Salt is something that dissolves in water, not a solvent. Alcohol is polar and can dissolve many substances, but not as universally as water. Oil is nonpolar and doesn’t mix with water, so it can’t dissolve the same range of substances. Water’s unique solvation ability explains why it’s considered the universal solvent.