Question

The cations in an aqueous solution that contains 0.150 m Ba(NO3)2 and 0.0800 m Ca(NO3)2 are to be separated by taking advantage of the difference in the solubilities of their sulfates. Ksp(BaSO4) 5 1.1 3 10210 and Ksp(CaSO4) 5 2.4 3 1025. What should be the concentration of sulfate ion for the best separatio?

Answer 1

Answer:Ba^2+ is a solid because the concerntration ofSO4 ion for the separation is 3.0×10^4M

Explanation: The equation for the reaction are:

1. BaSO4 ---->Ba^2+ SO4^2-

Ksp=1.1×10^-10

2.CaSO4 ------> Ca^2+ + SO4^2-

Ksp=2.4×10^-5

/Ba^2+/=0.150M

/Ca^2+/=0.080M

Calcuim sulfate is more soluble than barium sulfate, therefore add SO4^2- ion to leaveCa^2+ in the solution and precipitate Ba^2+ ions.

SO4^2-= 2.4×10^-5/0.080

SO4^2-=3.0×10^-4 M

ForCa^2+ ion to be left in the solution,reaction quotient must be less than the Ksp

Q=[Ca^2+][SO4^2-] <ksp

SO4^2- =Ksp/[Ca^2+]