The Best Answer for Calculate the concentration of all species in a 0.180 M solution of H2CO3?
Tricky. That's because there are NO molecules of H2CO3 in a solution of carbonic acid. Molecules of H2CO3 do not exist in liquid water. Carbonic acid is actually a solution of CO2 in equilibrium with small amounts of H+ ions and HCO3^- ions. The equilibrium lies far to the left, which means that most of the CO2 stays CO2.
CO2(aq) + H2O(l) <==> H+ + HCO3^-
HCO3^- is a weak acid, so there will be even less CO3^2- in solution.
HCO3^- <==> H+ + CO3^2-
____________
CO2(aq) + H2O(l) <==> H+ + HCO3^- ........... Ka = 4.3x10^-7 (*)
Ka = [H+][HCO3^-] / [CO2]
4.3x10^-7 = x² / 0.180
x = 2.8x10^-4 .... x = [H+] = [HCO3^-]
[H+] = 2.8x10^-4 ...... pH = 3.57
[OH-] = 1.0x10^-14 / 2.8x10^-4 = 3.6x10^-11
HCO3^- <==> H+ + CO3^2- ...... Ka = 4.8x10^-11
Ka = [H+][CO3^2-] / [HCO3^-]
4.8x10^-11 = [CO3^2-]
Lorem ipsum dolor sit amet, consectetur adipiscing elit,
sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,
quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor
in reprehenderit in voluptate velit esse cillum dolore eu fugiat.
SHOW ANSWER