Gen Chem 2: Ice Tables

Question

5. Build an ICE table for the acid dissociation of ascorbic acid.

• Suppose that the percent dissociation is small enough for [HOAsc]initial to be much larger than “x”.

• Use the relationship between total ion concentration and conductivity to algebraically-convert the Ka expression for the acid into an equation of the form “Conductivity = __________”, where the right side of the equation is an algebraic expression in terms of Ka and [HOAsc]initial.

• Use the equation you have derived to explain or deny the validity of your best fit curve type.

Answer 1

HOAsc <===> H⁺ + OAsc^-

[HOAsc]...........0............0.............Initial

-x....................+x...........+x...........Change

[HOAsc]-x........x.............x............Equilibrium

Ka = [H⁺][OAsc^-] / [HOAsc]

Ka = (x)(x) / [HOAsc]

Without any additional information about your conductivity measurements and methodology, I can't go any further relating conductivity to Ka and initial [HOAsc]. Maybe someone else will be able to add to this discussion.〉