Here's the breakdown:
* Hydrogen chloride (HCl) is a compound made up of one hydrogen atom and one chlorine atom. It's a colorless gas at room temperature.
* Hydrochloric acid is formed when hydrogen chloride gas dissolves in water. The HCl molecules react with the water molecules to form hydronium ions (H3O+) and chloride ions (Cl-). This process is what makes the solution acidic.
So, while hydrogen chloride (HCl) is the compound, hydrochloric acid is the solution of HCl in water.
