Sample Question: Take some Ethanol and Oxidizes Ethanol in presence of KMnO4 and produce 0.01 M axid. The acid react with strong base and produce 0.01 M salt. The dissociation constant of acid is 1.8 x 10-5.
According to question,
[Salt] = 0.01 M
[Acid] = 0.01 M
Ka = 1.8 x 10-5
Pka = — log (1.8 x 10-5) = 4.82
We know, pH = pka + log [Salt/Acid]
= 4.82 + log [0.01/0.01]
= 4.82 + log l = 4.82 [Ans.]
