Here's why:

* Hydrochloric acid is a strong acid that readily ionizes in solution to form hydrogen ions (H+) and chloride ions (Cl-).

* When hydrochloric acid reacts with a base (like a metal hydroxide or a metal oxide), it forms a chloride salt and water.

For example:

* HCl + NaOH → NaCl + H2O (sodium chloride salt is formed)

* 2HCl + MgO → MgCl2 + H2O (magnesium chloride salt is formed)

Let me know if you have any other questions!