Question

what is the chemical that refluxes into the esophagus, causing the burning pain of gerd?
bile
hydrochloric acid (hcl)
saliva
mucus

Explanation:

GERD (Gastroesophageal Reflux Disease) involves the backflow of stomach contents into the esophagus. The stomach produces hydrochloric acid to aid digestion, and this acidic substance irritates the sensitive esophageal lining, causing the characteristic burning pain (heartburn). Bile, saliva, and mucus do not cause this specific burning pain in GERD.

Answer:

Hydrochloric acid (HCl)