Final answer:
The chemical formula for the ion formed when hydrogen reacts with chloride is HCl, which dissociates in water to hydrogen ions (H+) and chloride ions (Cl-). These hydrogen ions form hydronium ions (H3O+) in solution.
Step-by-step explanation:
The chemical formula for the ion formed when hydrogen (H) reacts with chloride (Cl) is HCl. When hydrogen chloride is dissolved in water, it dissociates into hydrogen ions (H+) and chloride ions (Cl), a process which can be illustrated by the following chemical equation:
HCl(g) → H+ (aq) + Cl(aq)
In the presence of water, these hydrogen ions are not actually found as free protons; instead, they quickly combine with water molecules to form hydronium ions (H3O+), as shown in the formation of the hydronium ion equation:
HCl(aq) + H2O(l) → H3O+ (aq) + Cl(aq)