Understanding Conductivity
* Electric conductivity is the ability of a substance to allow the flow of electric current. This flow is achieved by the movement of charged particles (ions).
* Electrolytes are substances that conduct electricity when dissolved in a suitable solvent.
HCl in Water
1. Dissociation: When HCl dissolves in water, it undergoes ionization (a chemical reaction). The polar water molecules pull apart the HCl molecules, forming hydronium ions (H₃O⁺) and chloride ions (Cl⁻):
```
HCl(g) + H₂O(l) → H₃O⁺(aq) + Cl⁻(aq)
```
2. Mobility of Ions: The free-moving H₃O⁺ and Cl⁻ ions in the solution can carry electric current. When an electric field is applied, these ions migrate towards the oppositely charged electrodes, enabling the flow of electricity.
HCl in Benzene
1. Non-polar Solvent: Benzene (C₆H₆) is a non-polar solvent. It has no strong dipole moment to attract and pull apart the HCl molecules.
2. No Ionization: Without the influence of a polar solvent, HCl molecules remain intact in benzene. They do not form ions.
3. No Free Ions: Since there are no free ions present, there are no charged particles to carry an electric current. Therefore, the solution does not conduct electricity.
In Summary
The ability of HCl to conduct electricity depends entirely on its ability to form ions in solution. Water, being a polar solvent, promotes ionization of HCl, allowing it to conduct electricity. Benzene, being non-polar, does not promote ionization, so the solution remains non-conductive.
