Question

What is the Molarity (after mixing) of all the ions in the solution when 25.00 mL of an aqueous 1.055 M KCl solution are mixed with 50.00mL of an aqueous .6245 M Na2HPO4 solution? T and P are normal and constant.

Answer 1

any ion molarity = millimoles of that ion / total moles

a) K+ molarity = 25 x 1.055 / 25 + 50

                       = 0.352 M

b)

Cl- molarity = 25 x 1.055 / 25 + 50

                       = 0.352 M

c)

Na+ molarity = 2 x 50 x 0.6245 / 25 + 50

                       = 0.833 M

d)

HPO42- molarity = 50x 0.6245 / 25 + 50

                      = 0.416 M