We’re being asked **to determine the pH** of a **0.50 M weak acid that is 13 % ionized**.

Recall that the ** percent ionization **is given by:

$\overline{){\mathbf{\%}}{\mathbf{}}{\mathbf{ionization}}{\mathbf{=}}\frac{\mathbf{\left[}{\mathbf{H}}_{\mathbf{3}}{\mathbf{O}}^{\mathbf{+}}\mathbf{\right]}}{\mathbf{[}\mathbf{HA}{\mathbf{]}}_{\mathbf{initial}}}{\mathbf{\times}}{\mathbf{100}}}$

Also recall that ** pH** is given by:

$\overline{){\mathbf{pH}}{\mathbf{=}}{\mathbf{-}}{\mathbf{log}}{\mathbf{\left[}}{{\mathbf{H}}}_{{\mathbf{3}}}{{\mathbf{O}}}^{{\mathbf{+}}}{\mathbf{\right]}}}$

A weak acid was 13% ionized. What would be the pH of a 0.50 M solution and what is the pKa of the acid?

A. pH = 1.2; pKa = 2.0

B. pH = 4.3; pKa = 3.9

C. pH = 2.5; pKa = 3.2

D. pH = 4.8; pKa = 6.5

E. pH = 11.8; pKa = 11.8

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Weak Acids concept. If you need more Weak Acids practice, you can also practice Weak Acids practice problems.