Pure hydrogen chloride (HCl) is a gas at standard temperature and pressure. This gas can be dissolved in different solvents to make convenient acidic solutions. Water is the best and easiest solvent to dissolve HCl in since it is extremely polar. We call this solution hydrochloric acid. The HCl completely dissociates into H+ and Cl-. HCl gas dissolves much more poorly in toluene since toluene is a much less polar solvent. Since it dissolves less in toluene than in water then it is less acidic in toluene than in water. This is true at both room temperature and at 100 degrees. More of the gas will dissolve in toluene at the higher temperature, but it still will be less than the amount that dissolves in water.