The acid that reacts with sodium hydroxide (NaOH) to form a chloride solution is hydrochloric acid (HCl).

Here's the chemical reaction:

HCl (aq) + NaOH (aq) → NaCl (aq) + H₂O (l)

* HCl is hydrochloric acid.

* NaOH is sodium hydroxide.

* NaCl is sodium chloride, which dissolves in water to form a chloride solution.

* H₂O is water, which is also produced in the reaction.

This reaction is a neutralization reaction, where an acid and a base react to form salt and water.