Answer:
0.9
Explanation:
Considering the Henderson- Hasselbalch equation for the calculation of the pH of the buffer solution as:
pH=pKa+log[base]/[acid]
Given that :
pH = 8.6
pK2 will be used for the amino group which is = 9.60
So,
8.60=9.60+log[base]/[acid]
log[base]/[acid]=1.0
[base]/[acid] = 10
So,
[base] = 10 [acid]
Fraction is:
[base] / ([base] + [acid]) = 10 [acid] / 10 ([acid] + [acid]) = 10 / 11 = 0.9