A water sample is prepared by adding 10-4M NaCl, 10-3 M NaHCO3 and 10-4 M CaCl2 to water. Assume that when these salts dissolve, they dissociate to Na+, Cl-, Ca2+, and HCO3- and then do not react further.

a. Compute the ionic strength of the solution.

b. What is the activity of each dissolved ion if the infinitely solution approximation

applies and the infinite dilution scale is used? What is the activity of each ion if

the extended Debye-Huckel equation applies?

c. Calculate the activities of all ions if the NaCl concentration is increased by three

order of magnitude to 0.1 M to model an estuarine water.