Answer
pH of buffer = 10.03
Work Step by Step
1
(A) Given :
1. [conjugate base] = [C6H5O-] = 1.3 M
2. [acid] = [C6H5OH] = 1.2 M
3. pKa of Phenol (C6H5OH) = 10.00
2
(B) Formulae :
1. Henderson - Hasselbalch equation of a buffer :
pH = pKa + log [conjugate base] / [acid]
3
(C) Solution :
pH = pKa + log [conjugate base] / [acid]
So,
pH = 10.00 + log (1.3 / 1.2)
10.00 + 0.03
= 10.03
Hence, pH of the buffer is 10.03.
4
(D) Answer :
pH of buffer = 10.03
