Calculate OH - given H3 O + = 1.40 * 10^-4 M

3.16 X 10^-11 M is the [OH-] concentration when H3O + = 1.40 * 10^-4 M.

Explanation:

data given:

H30 + = 1.40 X 10^-4 M/

Henderson Hasslebalch equation to calculate pH=

pH = - log10 (H30+)

putting the values in the equation:

pH = - log 10 (1.40 X 10^-4 M)

pH = 3.85

pH + pOH = 14

pOH = 14 - 3.85

pOH = 10.15

The OH - concentration from the pOH by the equation:

pOH = - log10[OH-]

10.5 = - log10[OH-]

[OH-] = 10^-10.5

[OH-] = 3.16 X 10^-11 is the concentration of OH ions when hydronium ion concentration is 1.40 * 10^-4 M.