Ionic compounds conduct electricity when dissolved in water, because the free-floating ions can carry charge. The more ions you have, the more readily the solution will carry that charge. 10.0 mL of 0.10 M NH4Cl has only 0.001 mol of NH4+ and 0.001 mol of Cl-, whereas 10.0 mL of 0.30 NH4Cl has 0.003 mol of NH4+ and 0.003 mol of Cl-. The 0.10 M sample is a poorer conducted of electricity because it has less ions in solution.
