Dissolved ion concentration question?

Question

1 mole of which substance, when added to 1L water, would give the highest concentration of silver(I) ions:
A) silver(I) chloride
B) silver(I) phosphate
C) silver(I) sulfate
D) silver(I) perchlorate
E) silver(I) sulfide

Thought it was B

Answer 1

Sneaky question. You would be right except that silver phosphate is insoluble. Actually, one of these silver salts is much more soluble than the others, and that's the one you're after.

Answer 2

(A.) For Example, The solubility of silver chloride is 6.56x10-4 g/L.

For silver chloride, Ksp = [Ag+][Cl-], where the brackets mean concentration in mol/L. For every mole of silver chloride dissolved, one mole of silver ion and one mole of chloride ion are found in solution. Therefore, the first step in solving the problem is to convert the solutility from g/L to mol/L. The formula weight of silver chloride is 107.8 + 35.4 = 143.3. The solubility of AgCl is
6.56x10-4g 1 L x 1 mol 143.3 g = 4.58 x 10-6 mol/L

Therefore, [Ag+] = [Cl-] = 4.58 x 10-6 mol/L. Substituting this value into the solubility product expression gives:

Ksp= [Ag+][Cl-] = (4.58x10-6)(4.58x10-6)

= 20.9x10-12 = 2.09x10-11