## Chemistry: The Molecular Science (5th Edition)

$pH = 3.745$ $[OH^-] = 5.556 \times 10^{- 11}M$ This solution is acidic.
$pH = -log[H_3O^+]$ $pH = -log( 1.8 \times 10^{- 4})$ $pH = 3.745$ $[H_3O^+] * [OH^-] = Kw = 10^{-14}$ $1.8 \times 10^{- 4} * [OH^-] = 10^{-14}$ $[OH^-] = \frac{10^{-14}}{ 1.8 \times 10^{- 4}}$ $[OH^-] = 5.556 \times 10^{- 11}M$ $[H_3O^+] > [OH^-]$: Acidic solution; Assuming $25 ^{\circ}C$: pH < 7: Acidic solution;