When HCl dissociates, it produces 2 moles of ions: 1 mole of H+ ions and 1 mole of Cl- ions. This is because HCl is a binary acid, meaning that it contains only two elements: hydrogen and chlorine. When HCl dissociates, the hydrogen atom loses an electron to become a hydrogen ion (H+), and the chlorine atom gains an electron to become a chloride ion (Cl-).