The #HCl# dissociates in water to #H^+# and #Cl^-# because the attractive interactions between these ions and surrounding water molecules are stronger than between #HCl# and water.
Explanation:
Gastric juice consists of hydrochloric acid (#HCl#), potassium chloride (#KCl#) and sodium chloride (#NaCl#) as well as digestive enzymes produced by cells in the lining of the stomach.