# What is the molarity of hydrogen ions in a 2.7 M solution of the strong acid HCl?

You have a strong monoprotic mineral acid. $\left[{H}_{3} {O}^{+}\right]$ $=$ $2.7 \cdot m o l \cdot {L}^{-} 1$.
$H C l \left(g\right) + {H}_{2} O r i g h t \le f t h a r p \infty n s {H}_{3} {O}^{+} + C {l}^{-}$
This equilibrium lies strongly to the right. Thus, the concentration of hydronium ion, ${H}_{3} {O}^{+}$ $=$ $2.7 \cdot m o l \cdot {L}^{-} 1$.