The ksp of agcl is 1.8x10^-10 and the ksp of agi is 8.3x10^-17. a solution is .100m in i- and cl-. when a silver nitrate solution is slowly added to this mixture, what is the molarity of iodide ions when agcl just starts to precipitate?
a.) 1.0x10^-5m
b.) 9.1x10^-9m
c.) 8.3x10^-7m
d.) 4.6x10^-8m

Explanation:

The expression of the Ksp:

When the product of the concentrations of both ions equals the Ksp, the salt starts to precipitate.

For the AgCl:

Initially the concentration of I- was 0.1 M, due to the lower Ksp than the AgCl's, the AgI will precipite before. So, when AgCl starts to precipitate the concentration of I- will be in equilibrium, following the Ksp equation.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8