Chapter 14 - Acids and Bases - Questions for Review and Thought - Topical Questions - Page 652b: 33c

$pH = 3.745$ $[OH^-] = 5.556 \times 10^{- 11}M$ 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;