chemical equilibrium~

Fe3+ + SCN- <----> Fe(SCN)2+
in the experiment, 25com3 of 0.01M Fe2(SO4)3 and 25cm3 of 0.01M KSCN were mixed in a conical flask at room temp, and equilibrium was attained
the conc of Fe(SCN)2+ in the mixture was 0.0043M when equilibrium was attained

(a)cal the eqilibrium constant Kc for the above reaction at room temp.

(b)it is known that FePO4 (s) is insoluble in water. suggest what would be the effect on the equilibrium position if Na3PO4 (s)is added to the equilibrium mixture.