Recall the property of hydrochloric acid that makes it helpful for digestion.

Hydrochloric acid (HCl) is a strong acid that aids in digestion by breaking down food in the stomach. Here's how it works:

1. Hydrochloric acid is secreted by the cells in the lining of the stomach in response to eating and drinking.
2. The acid's high acidity level (pH 1.5 to 3.5) helps to break down food particles into smaller, more digestible pieces.
3. This acid also kills bacteria and other pathogens that may be present in the food, protecting the body from infections.
4. Additionally, HCl activates the enzyme pepsin, which further aids in the digestion of proteins.
5. The acidified food (chyme) is then passed into the small intestine where it is neutralized and digestion continues.

So, the property of hydrochloric acid that makes it helpful for digestion is its high acidity, which allows it to break down food particles, kill harmful bacteria, and activate digestive enzymes.