Question

If the pH is 4.5, what is the pOH ?

Answer 1

pH+pOH=14
4.5+pOH=14
pOH=14-4.5
pOH = 9.5

We know that
[H⁺][OH⁻]=10⁻¹⁴,so

-log([H⁺][OH⁻])=-log10⁻¹⁴
-log [H⁺]+ (- log[OH⁻])= - log10⁻¹⁴,
- log[H⁺] = pH
- log[OH⁻] = pOH
- log10⁻¹⁴=-(-14)log10=14*1=14
pH + pOH =14