Question

How would you use the Henderson-Hasselbalch equation to calculate the pH of a solution that is 0.17 M in HCHO_2 and 0.10 M in NaCHO2?

Answer 1

`pH=3.51`

Explanation:

In order to use the Henderson-Hasselbalch equation, you will need the acid dissociation constant `K_a` of formic acid, which is `K_a=1.8xx10^(-4)`.

Therefore, Henderson-Hasselbalch equation is written as:

`pH=pK_a+log(([NaCHO_2])/([HCHO_2]))`

`=>pH=3.74+log((0.10cancel(M))/(0.17cancel(M)))`

`=>pH=3.51`

Here is a video that explains buffer solution and the Henderson-Hasselbalch equation and it is origin and use.
Acid - Base Equilibria | Buffer Solution.