Answer
See explanation below.
Work Step by Step
1
(A) Given :
1. pH of the buffer = 2,.95
2. Ka of Acid (HPr) = 7.1 x 10^-4
2
(B) Formulae :
1. Henderson - Hasselbalch equation of a buffer : pH = pKa + log [base] / [acid]
2. pKa = -log(Ka)
3
(C) Solution :
1. pKa = -log (Ka)
= -log (7.1 x 10^-4)
= 3.15 .... (1)
2. pH = pKa + log [base] / [acid]
2.95 = 3.15 + log ([NO2-] / [HNO2])
-0.20 = log ([NO2-] / [HNO2])
[NO2-] / [HNO2] = 10^(-0.20) = 0.63
Hence, the component concentration ratio [NO2-] / [HNO2] is equal to 0.63