Answer is: this chemical reaction is dissociation of acid.
Chemical reaction of dissociation of propanoic acid:
CH₃CH₂COOH(aq) ⇄ CH₃CH₂COO⁻(aq) + H⁺(aq).
In aqueous solution propanoic acid dissociates (covalent bond between an electronegative oxygen atom and a hydrogen atom is broken by heterolytic fission) into conjugate base (anion CH₃CH₂COO⁻) of the acid and a hydrogen cation (H⁺).
Dissociation is a process in which molecules) separate into smaller particles such as atoms or ions.