Question

Given that the pH of a substance is 0.5, what is the [OH-]?
A. 3.16 x 10-14 mol/L
B. 1 x 10-11 mol/L
C. 3.16 x 10-7 mol/L
D. 1 x 10-4 mol/L

Answer 1

Since you're calculating \(\large[OH^-]\) first calculate the pOH.
pH + pOH = 14
So pOH = 14 - pH
14-0.5 = 13.5

So the pOH = 13.5
Now calculate the \(\large[OH^-]\) with the pOH

\(\large[OH^-]\)= \(\large10^{-pOH}\)
\(\large[OH^-]\)= \(\large10^{-13.5}\)