In: Chemistry
Calculate the concentrations of H2C2O4, HC2O4^ -, C2O4^ -2, and
H^+ species in a 0.430 M Oxalic Acid Solution
(Ka1 = 6.5 x 10^-2)
(Ka2 = 6.1 x 10^-5)
Be sure to answer in correct number of significant figures.
H2C2O4 = ________ M
HC2O4^- = _________ M
C2O4^2- = _________ x 10 ^ (scientific notation)
H^+ = ____________ M
suppose oxalic acid is H2A .
H2A --------------------------> H+ + HA-
0.430 0 0 -----------------> initial
0.430-x x x ----------------------> equilibrium
Ka1 = [HA-][H+]/[H2A]
6.5 x 10^-2 = x^2 / 0.430 -x
x^2 + 6.5 x 10^-2 x - 0.02795 = 0
x = 0.1378
x = [HA-] = [H+] = 0.1378 M
[H2A] = 0.430 - 0.1378 = 0.2922 M
H2C2O4 = _0.2922 M_______
HC2O4^- = __ 0.138 M_______
C2O4^2- = ____6.1 x 10 ^-5 M
H^+ = _____0.138 M___
note : Ka2 value equal to A-2 for diprotic acid