Final answer:
The nurse administering penicillin despite a known allergy is liable for malpractice due to negligence, and the recovery of the patient does not negate the breach of duty.
Step-by-step explanation:
The nurse's action of administering penicillin to a patient with a known allergy to the substance is a matter of medical malpractice due to negligence. This is because the nurse failed to act in a reasonable and prudent manner by not checking the patient's medical records, where the allergy was clearly noted. The standard of care in healthcare requires professionals to confirm and avoid known allergies when administering treatments. Therefore, the nurse is liable for malpractice. Even though the patient recovered, the severity of the incident could have resulted in more serious harm or death, as shown by the potential for anaphylactic shock due to allergic reactions.