Neutralization of gastric acid oxidation-reduction by aluminum hydroxide

A. ammonia is easy to liquefy. When liquid ammonia vaporizes, it absorbs a lot of heat, which makes the temperature of surrounding substances drop sharply, so ammonia is often used as refrigerant, so A is correct;

B. Silicon dioxide is the main raw material of optical fiber, and Si is located at the junction of metal and nonmetal, which has the properties of metal and nonmetal, so it can be used as semiconductor material, so B is wrong;

C. Aluminum hydroxide is amphoteric and can react with hydrochloric acid in gastric juice to generate salt and water, while aluminum hydroxide is less corrosive, so aluminum hydroxide is commonly used to neutralize gastric acid, so C is correct;

D. At room temperature, concentrated sulfuric acid reacts with iron to form a dense oxide film, which prevents further oxidation. This is a passivation phenomenon, so concentrated sulfuric acid is usually contained in iron containers at room temperature, so D is correct;

So choose B.