Question

What is the pH of a buffer system containing 0.52 M HCOOK and 0.30 M HCOOH?

A) 3.42
B) 4.18
C) 4.95
D) 5.71

Answer 1

The pH of a buffer system containing 0.52 M HCOOK and 0.30 M HCOOH can be calculated using the Henderson-Hasselbalch equation. The pH of the buffer system is approximately 4.24.

Step-by-step explanation:

The pH of a buffer system can be calculated using the Henderson-Hasselbalch equation, which relates the concentrations of the acid and its conjugate base to the pH of the solution.

In this case, the buffer system contains 0.52 M HCOOK (potassium formate) and 0.30 M HCOOH (formic acid). The pKa (the negative logarithm of the acid dissociation constant) of formic acid is 3.75.

Using the Henderson-Hasselbalch equation, the pH of the buffer system can be calculated as:

pH = pKa + log([conjugate base]/[acid])

Plugging in the values, we get:

pH = 3.75 + log(0.52/0.30) = 3.75 + 0.494 = 4.24

So, the pH of the buffer system is approximately 4.24. Therefore, the correct answer would be D) 5.71.