Final answer:
In HCl, 'H' represents hydrogen and 'Cl' represents chlorine. HCl becomes hydrochloric acid in water and dissociates into hydronium and chloride ions. Hydrochloric acid is a strong acid, fully ionizing in solution.
Step-by-step explanation:
In the chemical formula HCl, the letter 'H' represents a hydrogen atom, while the letter 'Cl' represents a chlorine atom. Hydrogen chloride (HCl) is a diatomic molecule composed of these two elements. When dissolved in water, HCl becomes hydrochloric acid, behaving as a strong acid by completely dissociating into hydronium ions (H3O+) and chloride ions (Cl−). The dissociation of HCl in water is given by the chemical reaction: HCl(g) + H2O(l) → H3O+(aq) + Cl−(aq).
Strong acids like hydrochloric acid are known for their property of being completely ionized in aqueous solutions. This process significantly contributes to the concentration of hydrogen ions ([H+]) in the solution, which determines the solution's acidity. As a strong acid, an aqueous solution of hydrochloric acid will have a high concentration of hydrogen ions and a corresponding low concentration of hydroxide ions ([OH−]) due to the autoionization of water.