Final answer:
The inhalational anesthetic most likely to be associated with junctional arrhythmia in the described case is Halothane, due to its known cardiac side effects.
Step-by-step explanation:
The inhalational anesthetic most likely associated with junctional arrhythmia in a 56-year-old, 75-kg man undergoing general anesthesia for a right colectomy is Halothane. Among the options given, halothane is known for its adverse effects on the cardiac rhythm, which includes the risk of developing arrhythmias.
The safety of volatile anesthetics such as halothane, enflurane, and isoflurane have been questioned due to their side effects, with halothane in particular being associated with higher rates of miscarriages among female operating room workers exposed to it. Therefore, halothane would most likely be the inhalational anesthetic agent related to the arrhythmia in this case.