Answer to Question #114107 in Organic Chemistry for Addie

Question

Calculate the [OH-], pH, and pOH if the [H3O+] = 2.7x10-7 M

Answer 1

Solution:

The pH is calculated using the expression:

pH = - log[H₃O⁺]

pH = - log(2.7×10^-7) = 6.568 = 6.57

pH = 6.57

The pH and pOH of a water solution at 25^oC are related by the following equation:

pH + pOH = 14.

Then,

pOH = 14 - pH

pOH = 14 - 6.57 = 7.43

pOH = 7.43

The pOH is calculated using the expression:

pOH = - log[OH^-]

[OH^-] = 10^-pOH

[OH^-] = 10^-7.43 = 3.7×10^-8

[OH^-] = 3.7×10^-8 M

Answer:

pH = 6.57

pOH = 7.43

[OH^-] = 3.7×10^-8 M