Water’s ability to dissolve many substances is largely due to which property?

• A. Polarity of water molecules
• B. Color of water
• C. High viscosity
• D. Low surface tension

Answer: (A)

Water dissolves many substances primarily because of its polarity. The molecule has a bent shape with a partial negative charge on oxygen and partial positive charges on the hydrogens, giving it a strong dipole. This allows water to interact favorably with charged and polar solutes: cations are surrounded by the negatively charged oxygen ends, and anions by the positively charged hydrogen ends, forming hydration shells that stabilize the dissolved ions and help pull the lattice apart. For polar covalent solutes, water can form dipole–dipole interactions or hydrogen bonds, reducing the solute’s intermolecular forces and promoting dissolution. This is why salts and sugars dissolve well in water, while nonpolar substances don’t—because they don’t interact well with the polar water molecules. The other properties listed—color, viscosity, and surface tension—do not explain water’s ability to dissolve substances.