Final answer:
Chemical substances such as acids, alkalis, and strong oxidizing agents can cause burns to the oral mucosa when ingested.
Step-by-step explanation:
Chemical substances that can cause burns to the oral mucosa when ingested include acids (such as hydrochloric acid), alkalis (such as sodium hydroxide), and strong oxidizing agents (such as bleach). When these chemicals come into contact with living tissues, they can cause damage through amide and ester hydrolysis, breaking down proteins and lipids. Ingestion of these substances can lead to damage in the esophagus and stomach.