# Question #ee8bb

Jul 21, 2017

Yes, it is.

#### Explanation:

Ammonium nitrate is indeed an acidic salt. Here's why.

Ammonium nitrate is soluble in water, which implies that it dissociates completely in aqueous solution to produce ammonium cations, ${\text{NH}}_{4}^{+}$, and nitrate anions, ${\text{NO}}_{3}^{-}$.

${\text{NH"_ 4"NO"_ (3(aq)) -> "NH"_ (4(aq))^(+) + "NO}}_{3 \left(a q\right)}^{-}$

Now, the ammonium cation acts as a weak acid in aqueous solution, meaning that it can donate its proton to a water molecule to form hydronium cations, ${\text{H"_3"O}}^{+}$, and ammonia, $\text{NH} - 3$, a weak base.

${\text{NH"_ (4(aq))^(+) + "H"_ 2"O"_ ((l)) rightleftharpoons "NH"_ (3(aq)) + "H"_ 3"O}}_{\left(a q\right)}^{+}$

Since the presence of the ammonium cations in solution causes an increase in the concentration of the hydronium cations, which, consequently, causes the $\text{pH}$ of the solution to decrease compared with that of pure water at the same temperature, you can say that ammonium nitrate is an acidic salt.

In fact, the $\text{pH}$ of an ammonium nitrate solution at room temperature is equal to $5.25$ $\to$ see here for more info on that.

Also, note that the nitrate anion does not hydrolyze because nitric acid si a strong acid, which implies that the nitrate anion cannot accept a proton from a water molecule

$\textcolor{red}{\cancel{\textcolor{b l a c k}{{\text{NO"_ (3(aq))^(-) + "H"_ 2"O"_ ((l)) -> "HNO"_ (3(aq)) + "OH}}_{\left(a q\right)}^{-}}}}$