What is the universal solvent?

• A. H2O
• B. O2
• C. CO2
• D. NH3

Answer: (A)

Water’s polarity and ability to form extensive hydrogen-bonding networks let it interact with a wide range of substances. The partial negative charge on oxygen and partial positive charges on hydrogens enable water to surround and stabilize ions and polar molecules, breaking apart ionic lattices and dissolving salts, acids, bases, and many organic compounds with polar groups. This versatility is why water is called the universal solvent: it dissolves more solutes than any other common liquid under typical conditions.

Nonpolar gases like oxygen and carbon dioxide don’t have the necessary interactions to dissolve many solutes, and while ammonia is a polar solvent, it doesn’t match water’s broad dissolving ability across so many different classes of substances.