# Question #b0cc2

Sep 9, 2015

If you mix these substances in equal amounts, you get a solution that has a pH equal to $7$.

#### Explanation:

Sodium hydroxide, a strong base, will react with hydrochloric acid, a strong acid, to produce sodium chloride, a soluble salt, and water.

This reaction is called a neutralization reaction because when you mix equal amounts of strong base and strong acid, the pH of the resulting solution is neutral, i.e. equal to $7$.

Both sodium hydroxide and hydrochloric acid are dissociated in aqueous solution

${\text{NaOH"_text((aq]) -> "Na"_text((aq])^(+) + "OH}}_{\textrm{\left(a q\right]}}^{-}$

and

${\text{HCl"_text((aq]) -> "H"_text((aq])^(+) + "Cl}}_{\textrm{\left(a q\right]}}^{-}$

When you mix equal amounts of sodium hydroxide and hydrochloric acid, the hydroxide ions produced by the dissociation of the base will react with the hydrogen ions produced by the acid to form water.

The sodium cations and chloride anions will be dissociated in the resulting solution. The overall reaction is

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

The net ionic equation is

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

If you have a complete neutralization, meaning that equal amounts of hydronium and hydrogen ions react, the pH of the resulting solution will be equal to $7$, which is the pH of water at ${20}^{\circ} \text{C}$.