Here's why:
* Polarity: HCl is a polar molecule because of the difference in electronegativity between hydrogen and chlorine. This creates a partial positive charge on the hydrogen atom and a partial negative charge on the chlorine atom.
* Non-polar Solvents: Toluene, a hydrocarbon, is a non-polar solvent. Non-polar solvents are unable to effectively separate the positive and negative charges of polar molecules like HCl.
* Ionization: For a solution to conduct electricity, it needs ions (charged particles) to carry the electrical current. In non-polar solvents like toluene, HCl molecules remain intact and do not dissociate into ions (H+ and Cl-).
* No Free Ions: Without free ions in the solution, there is no pathway for electrical current to flow, thus explaining the lack of conductivity.
In contrast: When HCl gas is dissolved in water (a polar solvent), it readily dissociates into H+ and Cl- ions, leading to a highly conductive solution.
