In: Chemistry
Find the pH of each of the following solutions of mixtures of acids.: 1. 0.170 M in HNO2 and 9.0×10−2 M in HNO3 2. 0.190 M in HCHO2 and 0.23 M in HC2H3O2 3. 5.0×10−2 M in acetic acid and 5.0×10−2 M in hydrocyanic acid
1. 0.170 M in HNO2 and 9.0×10−2 M in HNO3
Ka of HNO2 = 5.6 x 10^-4
concentration = 0.170 M
HNO2 --------------> H+ + NO2-
0.170 0 0
0.170 - x x x
Ka = x^2 / 0.170 - x
5.6 x 10^-4 = x^2 / 0.170 - x
x = 9.48 x 10^-3
[H+] from HNO2 = 9.48 x 10^-3 M
[H+] from HNO3 = 9.0 x 10^-2 M
total [H+] = 0.09948 M
pH = -log [H+] = -log (0.09948)
pH = 1.0