Question

A) A solution of Na2CO3 is added dropwise to a solution that contains 1.23×10⁻² M Fe2+ and 1.59×10⁻² M Cd2+. What concentration of CO32− is need to initiate precipitation? Neglect any volume changes during the addition. Answer is =

[CO32−] =

1.13×10−12 M

B)

In the solution from Part A, what will the concentration of CO32− be at the moment before Fe2+ begins to precipitate?

Answer 1

Solutiton Griven that Na, cog sadded daopoise do a Lolution Contain 231Mfe 1-5q x1M The mmum Co on concentaation. Jieq^uzedfo P se ciptaion of feco aod Cd o Can be calculated foltos R-towi o to- .23X10 ) 2.10 X1o 23x10 013x 109 for Cdco3 -2 .80x10 9 (03 -5q10 - ia Thy the mamum Coacentxation of aonate fo eaed to ate precptation 1320 x'H 320

jurt befoe Pe begay The oaceata-1on of Co1 to paedptate