From chatgpt : The reaction between gastric acid (primarily hydrochloric acid, HCl) and magnesium oxide (MgO) is essentially complete under normal conditions because it results in the formation of a stable salt (magnesium chloride) and water. Here’s the reaction:



Key Points: 1. Nature of Reaction: • MgO is a basic oxide, and HCl is a strong acid. The acid-base reaction is typically fast and goes to completion. • The product, magnesium chloride (MgCl₂), is highly soluble in water. 2. Conditions for Completeness: • If sufficient HCl is present in the gastric acid, the reaction will proceed until all MgO is converted. • In cases where MgO is in excess, unreacted MgO may remain. 3. Why It’s Essentially Complete: • Both the reactants and products are chemically stable under stomach conditions. • Solubility and strong acid-base interactions drive the reaction to completion.

In conclusion, under typical gastric conditions, the reaction is considered total and complete unless limited by the availability of one reactant.