Question

What is the pH of a buffer solution that is 0.222 M in lactic acid and 0.132 M in sodium lactate? The Ka of lactic acid is 1.4 × 10^-4.

A) 14.23
B) 10.38
C) 5.39
D) 3.62
E) 4.08

Answer 1

The Answer is 4.08

Step-by-step explanation:

to find the ph of a buffer solution use this formula PH=Pka=log(Acid/base)

we are given Ka to find pka we use Pka= -log(ka) so,

Pka= -log(1.4 *10^-4)

Pka= 3.854

Now we can do.

.222M Lactic Acid = Acid

.132M Sodium Lactate = Base

Ph = 3.854+log(.222/.132)

= 4.08