Here's why:
* Acids like hydrochloric acid release hydrogen ions (H+) in solution.
* Bases like sodium hydroxide release hydroxide ions (OH-) in solution.
When these two solutions are mixed, the hydrogen ions and hydroxide ions react to form water (H2O):
H+ + OH- → H2O
This reaction also produces a salt, in this case, sodium chloride (NaCl):
HCl + NaOH → NaCl + H2O
The formation of water and salt is characteristic of a neutralization reaction.