Question

A solution with a pH of 9 has a [OH-] concentration of
A. 1.0 × 10–14 mol/L.
B. 1.0 × 10–9 mol/L.
C. 1.0 × 10–5 mol/L.
D. 1.0 × 10–7 mol/L.

Answer 1

@JFraser

Answer 2

pH=-log[H+]
Kw= [H+][OH-]=10^-14

Answer 3

use the relationship between pH and pOH, and the mathematic relationship that turns pOH into concentration\[pH + pOH = 14\]and\[10^{-pOH} = [OH^{-1}]\]