Molten potassium chloride conducts electricity due to the presence of . A. Free electron B. Free ions C. Free molecules D. Atom of potassium & chloride
The Correct Answer and Explanation is:
The correct answer is B. Free ions.
Explanation:
Molten potassium chloride (KCl) conducts electricity because it contains free ions that are able to move when an electric field is applied. Here’s a detailed explanation:
- Ionic Compound Nature: Potassium chloride is an ionic compound made up of potassium ions (K⁺) and chloride ions (Cl⁻). These ions are held together by strong electrostatic forces known as ionic bonds.
- Conductivity in Solid vs. Molten State:
- In the solid state, potassium chloride does not conduct electricity because the ions are locked in a rigid lattice structure. These ions cannot move freely, so they cannot carry an electric current.
- However, when potassium chloride is molten (melted), the ionic bonds are broken, and the potassium ions (K⁺) and chloride ions (Cl⁻) are free to move within the liquid. This mobility of charged particles allows the molten KCl to conduct electricity.
- Why Not Free Electrons or Molecules?
- Free Electrons (A): Free electrons are responsible for electricity conduction in metals (like copper or aluminum), where the electrons move through a lattice of metal atoms. However, molten KCl is an ionic compound, not a metal, and it doesn’t have free electrons available to conduct electricity.
- Free Molecules (C): The conduction of electricity in molecular compounds (like gases or covalent liquids) depends on the presence of charged particles, but KCl is an ionic compound, not a molecular one. It does not have neutral molecules that could carry an electric charge.
- Atoms of Potassium and Chloride (D): Potassium and chloride atoms, when combined, form ions, but as individual atoms, they do not carry an electric charge that would facilitate conduction.
Thus, molten potassium chloride conducts electricity because the ions (K⁺ and Cl⁻) are free to move and carry an electrical current, making free ions the correct answer.
