Which of the following types of substances conduct electricity when dissolved in water?

• A. Nonpolar molecules such as O2
• B. Solid metals such as Cu
• C. Ionic compounds such as NaCl
• D. Covalent compounds such as C6H12O6 (glucose)

Answer: (C)

Verified step by step guidance

1. Understand that electrical conductivity in aqueous solutions depends on the presence of charged particles (ions) that can move freely to carry electric current.
2. Recognize that nonpolar molecules like O\_2 do not dissociate into ions in water, so they do not conduct electricity when dissolved.
3. Note that solid metals such as Cu conduct electricity in their solid metallic form due to free electrons, but when placed in water, they do not dissolve to produce ions and thus do not conduct electricity in solution.
4. Identify that ionic compounds like NaCl dissociate into their constituent ions (Na\^+ and Cl\^-) when dissolved in water, allowing the solution to conduct electricity effectively.
5. Understand that covalent compounds such as C\_6H\_{12}O\_6 (glucose) dissolve as intact molecules without producing ions, so their aqueous solutions do not conduct electricity.