Fe 3+ + SCN- --> FeSCN 2+
.......Fe 3+ .......SCN-.........FeSCN 2+
I.......0.04..........0.001..............
C........-x...............-x.............
E.....0.04-x.....0.001-x...........x
Keq = 203.4 = x / (0.04-x)(0.001-x)
203.4 = x / (x^2 - 0.041x + 4x10^-5)
203.4x^2 - 8.34x + 0.00094 = x
203.4x^2 - 9.34x + 0.00094 = 0
x = -0.0001M or 0.0458M
so, using your Keq, there would be no SCN- or Fe 3+ left.....all would be in the form of FeSCN 2+
