Which binary acid is primarily responsible for the acidity of gastric juice in the human stomach?

• A. Hydroiodic acid, $HI$
• B. Hydrochloric acid, $HCl$
• C. Hydrofluoric acid, $HF$
• D. Hydrobromic acid, $HBr$

Answer: (B)

Verified step by step guidance

1. Understand that gastric juice in the human stomach is acidic due to the presence of a specific binary acid, which is a compound consisting of hydrogen and one other element.
2. Recall that the primary acid responsible for the acidity of gastric juice is a strong acid commonly found in the stomach environment.
3. Identify the options given: Hydroiodic acid (HI), Hydrochloric acid (HCl), Hydrofluoric acid (HF), and Hydrobromic acid (HBr).
4. Consider the biological role and common knowledge in chemistry that hydrochloric acid (HCl) is secreted by the stomach lining to aid digestion and maintain an acidic pH.
5. Conclude that hydrochloric acid (HCl) is the binary acid primarily responsible for the acidity of gastric juice in the human stomach.