In: Chemistry
Calculate the pH of a 0.340M NaO2CCO2H solution. pKa1 = 1.250 and pKa2 = 4.266. Apparently the answer is 2.79 but can someone explain this?
a. -0.029
b. 3.38
c. 2.79
d. 4.89
e. 2.37
answer : e) 2.37
NaO2CCO2H <-----------------------> NaO2CCO2- + H+
0.34 0 0
0.34 - x x x
Ka2 = x^2 /0.34 - x
5.42 x 10^-5 = x^2 /0.34 - x
x = [H+] = 4.30 x 10^-3 M
pH = -log [H+] = -log (4.30 x 10^-3)
pH = 2.37