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,

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