We’re being asked to **calculate the pH of a solution that is 1.00 M HF and 0.20 M KF**.

A solution that contains a **weak acid** and its **conjugate base** is a **buffer solution**. The pH of a buffer solution can be determined using the **Henderson-Hasselbalch equation**.

$\overline{){\mathbf{pH}}{\mathbf{=}}{{\mathbf{pK}}}_{{\mathbf{a}}}{\mathbf{+}}{\mathbf{log}}{\mathbf{}}\mathbf{\left(}\frac{\mathbf{conjugate}\mathbf{}\mathbf{base}}{\mathbf{weak}\mathbf{}\mathbf{acid}}\mathbf{\right)}}$

**Given solution:**

The solution is composed of 1.00 M HF and 0.20 M KF.

• **HF** is a **weak acid**

• the anion in KF is the conjugate base

Calculate the pH of a solution that is 1.00 M HF and 0.20 M KF. K_{a} = 7.24 x 10^{-4}

a. 2.44

b. 3.84

c. 0.70

d. 3.14

e. 2.84

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 Buffer concept. You can view video lessons to learn Buffer. Or if you need more Buffer practice, you can also practice Buffer practice problems.