Zinc ion reacts with excess CN? To form a colorless complex ion, Zn(CN)42, which has a formation constant Kf = 4.2x10^19. Compute the concentration of Zn2+ in a solution prepared by mixing equal volumes of 5.0x103 M Zn(NO3)2 and 0.10 M NaCN. Ignore the hydrolysis of CN(aq).