Question

If equal volumes of 0.8M sodium lactate and 0.4M lactic acid are mixed, and the pKa of lactic acid is 3.86,

the final of the solution pH should be

Answer 1

Answer:

4.16

Explanation:

Considering the Henderson- Hasselbalch equation for the calculation of the pH of the buffer solution as:

pH=pKa+log[base]/[acid]

Where Ka is the dissociation constant of the acid.

Given that:

pKa = 3.86

Given, concentration of acid = [acid] = 0.4 M

concentration of base = [base] = 0.8 M

So,

pH=3.86+log(0.8/0.4) = 4.16