Asked by Kelly
The Ka values of H2CO3 are shown below.
Ka1 4.6 10-7
Ka2 4.4 10-11
What is the pH of a 0.17 M solution of Na2CO3?
Ka1 4.6 10-7
Ka2 4.4 10-11
What is the pH of a 0.17 M solution of Na2CO3?
Answers
Answered by
DrBob222
Write the hydrolysis equation for carbonate ion.
CO3^-2 + HOH ==> HCO3^- + OH^-
Now set up an ICE chart and substitute into the Kb expression.
Kb = (Kw/k2) = (HCO3^-)(OH^-)/(CO3^-2)
(HCO3^-)= (OH^-) = x
(CO3^-2) = 0.17
You know Kw and k2.
Solve for x and convert to pH.
Post your work if you get stuck.
CO3^-2 + HOH ==> HCO3^- + OH^-
Now set up an ICE chart and substitute into the Kb expression.
Kb = (Kw/k2) = (HCO3^-)(OH^-)/(CO3^-2)
(HCO3^-)= (OH^-) = x
(CO3^-2) = 0.17
You know Kw and k2.
Solve for x and convert to pH.
Post your work if you get stuck.