# How do you calculate the pH of an acid?

Dec 28, 2016

In fact you measure the $p H$ of an acid..........

#### Explanation:

$p H = - {\log}_{10} \left[{H}_{3} {O}^{+}\right]$.

For strong acids, i.e. $H X \left(X = C l , B r , I\right) , H C l {O}_{4}$, ${H}_{2} S {O}_{4}$, the following equilibrium lies strongly to the right.........

$H X \left(a q\right) + {H}_{2} O \left(l\right) r i g h t \le f t h a r p \infty n s {H}_{3} {O}^{+} + {X}^{-}$

If, say, $0.1 \cdot m o l \cdot {L}^{-} 1$ monoacid is used, the solution is stoichiometric in ${H}_{3} {O}^{+}$.

$p H = - {\log}_{10} \left(0.1\right) = - {\log}_{10} \left({10}^{-} 1\right) = 1$.