问答题

0.02000 mol/L EDTA solution (10.05 mL) was mixed with 0.02000 mol/L Pb(NO3)2 solution (10.00 mL) [lgK(PbY)=18.0, pH=5.0, lgY(H)=6.5]. The concentration of uncomplexed Pb2+ is 
[填空1]mol/L。