# What is the pH of 300 mL of 0.007 M HCl?

$p H = - {\log}_{10} \left[{H}_{3} {O}^{+}\right]$
Hydrochloric acid is stoichiometric in ${H}_{3} {O}^{+}$.
$- {\log}_{10} \left(0.007\right) = 2.15$. The volume of the solution is unimportant.