Why is pure water considered a poor conductor of electricity?

• A. It lacks ions to conduct electricity effectively
• B. It has many ions that conduct electricity
• C. It conducts as well as saltwater
• D. It is a strong conductor due to hydrogen bonds

Answer: (A)

Conduction in liquids relies on mobile charged particles to carry current. Pure water has very few such carriers because it only slightly ionizes into hydronium and hydroxide ions. At room temperature the ion concentration is about 1e-7 moles per liter for each ion, so only a tiny amount of charge can flow. That’s why pure water conducts electricity poorly. When salts are dissolved, many more ions are present, providing more charge carriers and greatly increasing conductivity. Hydrogen bonds between water molecules don’t create a conducting path; conduction comes from ions moving under the electric field. So the correct idea is that pure water lacks sufficient ions to conduct electricity effectively.