Question

1. Please provide the balanced net ionic equations for the following reactions:

a. KI in aqueous solution

b. NH4)2S2O8 in aqueous solution

c. KI and (NH4)2S2O8 in aqueous solution

i. If starch is added to the solution initially, what color will the final solution be and what causes this color change?

d. Na2S2O3 in aqueous solution

e. If Na2S2O3 is added to the solution in part c, what reactions will occur? Indicate the color of each side of each reaction.

Answer 1

1. Net ionic equations

a. KI in aqueous solution

KI(aq) ---> K+(aq) + I-(aq)

b. (NH4)2S2O8(aq) ---> 2NH4+(aq) + S2O8^2-(aq)

c. KI and (NH4)2S2O8 in aqueous solution

S2O8^2-(aq) + 3I-(aq) ---> 2SO4^2-(aq) + I3^-(aq)

i. If starch is added to solution, the final color of solution would be dark blue-black.

d. Na2S2O3 in aqueous solution

Na2S2O3(aq) ---> 2Na+(aq) + S2O3^2-(aq)

e. Na2S2O3 added to c.

2S2O3^2-(aq) + I3-(aq) ---> S4O6^2-(aq) + 3I-(aq)

Colorless --------------------------------> Blue-black