Answer
$pH = 5.342$
$[H_3O^+] = 4.545 \times 10^{- 6}M$
This solution is acidic.
Work Step by Step
$[OH^-] * [H_3O^+] = Kw = 10^{-14}$
$ 2.2 \times 10^{- 9} * [H_3O^+] = 10^{-14}$
$[H_3O^+] = \frac{10^{-14}}{ 2.2 \times 10^{- 9}}$
$[H_3O^+] = 4.545 \times 10^{- 6}M$
$pH = -log[H_3O^+]$
$pH = -log( 4.545 \times 10^{- 6})$
$pH = 5.342$
$[H_3O^+] > [OH^-]$: Acidic solution.
Assuming $25 ^{\circ} C$: pH < 7: Acidic solution.
