Phenylacetic acid (HC8H7O2) is one of the substances that accumulates in the blood of persons with phenylketonuria, an inherited disorder that can cause mental retardation and even death. A 0.033 M solution of HC8H7O2 is found to have a pH of 2.9. ?

What is the pKa of HC8H7O2?

1 Answer
Mar 27, 2018

4.3

Explanation:

#sf(pH=1/2[pK_a-loga])#

Where #sf(a)# is the concentration of the weak acid.

#:.# #sf(2.9=1/2[pK_a-log(0.033)])#

#sf(2.9=1/2 pK_a-1/2(-1.481))#

#sf(2.9=1/2pK_a+0.7407)#

#sf(1/2pK_a=2.159)#

#sf(pK_a=4.32)#