Incorrect Find the formal concentration of FeY^2 by multiplying the dilution fac
ID: 957734 • Letter: I
Question
Incorrect Find the formal concentration of FeY^2 by multiplying the dilution factor by the initial concentration of Fe^2+. Find the formal concentration of EDTA by multiplying the dilution factor of EDTA with the concentration of EDTA in the solution that is added Construct an equilibrium table for the formation of the complex. Set tho initial concentration of FeY2* equal to the formal concentration of FeY2 . and the initial concentration of EDTA to the formal concentration of EDTA. Equate (he equilibrium expression to and solve for x the concentration ol Fe^2+.Explanation / Answer
equivalent volume of EDTA = Ve
Ve x 0.03574 = 25 x 0.02180
Ve = 15.25 mL
EDTA : 18.50 mL
FeY-2 = 25 / (25+18.50) x 0.02180 = 0.0125 M
formal concentration of EDTA:
(18.50 -15.25) x 0.03574 / (25+18.50) = 0.00267 M
Fe+2 + EDTA -------------------> FeY-2
0 0.00267 0.0125
x 0.00267 +x 0.0125-x
conditional formation constant for this system = 5.79 x 10^7
5.79 x 10^7 = ( 0.0125-x) / x (0.00267 +x)
x = 8.064 x 10^-8
x = [Fe+2] = 8.064 x 10^-8 M
pFe+2 = -log [Fe+2] = -log (8.064 x 10^-8)
pFe+2 = 7.09