1 Calculate the solution potential for a solution containing

1.   Calculate the solution potential for a solution containing 20 mM ClO-, 5 mM Cl-, and 273 M O2?

2.   Based on the Pourbaix diagram:
a.   What is the solution potential of a 1 M aqueous solution of sodium iodate at pH 6?
b.   What is the pKa of iodic acid?
c.   Under what pH conditions is I2 stable with respect to disproportionation?
d.   How many protons are involved in the oxidation of IO3- to IO4-?

1.B Io IO,/H,10s 1.6 14 F HIO H210 1.2 I0 0.8 0.6 0.4 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Solution

1. The solute potential (SP) determines the flow of osmosis. It depends on the

a. concentration of solute,

b. The number of ions coming from each molecule

c. temperature

The formula for calculation of SP = -(number of ions per each molecule)X(molarity)X(pressure constant)X(temperature in Kelvin)

Pressure constant has an universal value of : 0.0831 lit.bar.mole^-1.temp^-1

For this given problem, the temperature is not given so we take it as 20degC.The negative ions given in the problem must co-exist with its positive counterpart and oxygen wont contribute to the solute potential

The solute potential of ClO^- = -2x0.02x0.0831x293 bar=-0.973932

and Cl^- is = 2x.005x0.0831x293 = -0.243483 bar respectively.