# Is NH_4ClO_4 acidic?

A solution of $\text{ammonium perchlorate}$ would be slightly acidic in water.
$\text{Ammonium ion}$ is the conjugate acid of a weak base, $\text{ammonia}$; $\text{perchlorate anion}$ is the conjugate base of a strong acid, $H C l {O}_{4}$. And thus the acid base behaviour of the salt depends on the ammonium ion. Solution of ammonium perchlorate would be slightly acidic, and its $p H$ governed by the equilibrium:
$N {H}_{4}^{+} + {H}_{2} O \left(l\right) r i g h t \le f t h a r p \infty n s N {H}_{3} \left(a q\right) + {H}_{3} {O}^{+}$