# Question #2df58

Apr 8, 2017

The chloride anion, ${\text{Cl}}^{-}$.

#### Explanation:

Dissolving hydrogen chloride in water will get you hydrochloric acid, which is essentially an aqueous solution of hydrogen chloride.

${\text{HCl"_ ((g)) -> "HCl}}_{\left(a q\right)}$

Hydrochloric acid is a strong acid, which means that it ionizes completely in aqueous solution to produce two ions, the hydronium cation, ${\text{H"_3"O}}^{+}$, and the chloride anion, ${\text{Cl}}^{-}$.

${\text{HCl"_ ((aq)) + "H"_ 2"O"_ ((l)) -> "H"_ 3"O"_ ((aq))^(+) + "Cl}}_{\left(a q\right)}^{-}$

Hydrochloric acid solutions have very high concentrations of hydronium cations. Consequently, hydrochloric acid solutions will have a very low $\text{pH}$.

When it comes to hydrochloric acid solutions, we're usually more interested in the hydronium cations, so I'm guessing that the "other ion" you mentioned would be the chloride anion.