# Question 2e6ba

Sep 1, 2015

Hydrochloric acid, $\text{HCl}$.

#### Explanation:

Sodium hydroxide is a strong base, which means that it will exist as sodium cations, ${\text{Na}}^{+}$, and hydroxide anions, ${\text{OH}}^{-}$, in aqueous solution.

In order to produce sodium chloride, $\text{NaCl}$, which is a soluble salt that exists as sodium ations and chloride anions, ${\text{Cl}}^{-}$ in aqueous solution, you need to provide the sodium hydroxide solution with two things

• Hydrogen ions, or protons, ${\text{H}}^{+}$, to neutralize the hydroxide ions;
• chloride ions, "Cl^(-)#.

This implies that you in order for the reaction to produce sodium chloride, you need a strong acid that dissociates into hydrogen ions and chloride ions in solution.

Hydrochloric acid, $\text{HCl}$, does just that. When you mix these two solutions in a $1 : 1$ mole ratio, the hydrogen ions will react with the hydroxide ions to produce water, leaving you with dissolved sodium chloride.

${\text{NaOH"_text((aq]) + "HCl"_text((aq]) -> "NaCl"_text((aq]) + "H"_2"O}}_{\textrm{\left(l\right]}}$

This reaction is called a neutralization reaction because you use an acid to neutralize a base, leaving the solution at a neutral pH afterwards.