# What is pH for a solution whose [H_3O^+]=6.7xx10^-5*mol*L^-1?

##### 1 Answer
Aug 19, 2016

$p H = 4.17$

#### Explanation:

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

Thus $p H = {\log}_{10} \left(6.7 \times {10}^{-} 5\right)$ $=$ $- \left(- 4.17\right)$

Note that when we write ${\log}_{a} b = c$, we are looking for the power to which we raise the base $a$ to get $b$; here ${a}^{c} = b$. What are ${\log}_{10} 100$, ${\log}_{10} 1000000$, and ${\log}_{10} 0.001$?