## Chemistry and Chemical Reactivity (9th Edition)

pH = 2.125 - Hydroxide ion concentration = $1.333 \times 10^{-12}M$
- HCl is a strong acid, therefore: $[H_3O^+] = [HCl] = 0.0075M$ 1. Calculate the pH Value $pH = -log[H_3O^+]$ $pH = -log( 7.5 \times 10^{- 3})$ $pH = 2.125$ 2. Calculate the $[OH^-]$: $[H_3O^+] * [OH^-] = Kw = 10^{-14}$ $7.5 \times 10^{- 3} * [OH^-] = 10^{-14}$ $[OH^-] = \frac{10^{-14}}{ 7.5 \times 10^{- 3}}$ $[OH^-] = 1.333 \times 10^{- 12}M$