Question #44564

Two ionization isomers, P and Q, of a coordination complex with the empirical formula \ce{Co(NH3)5(NO2)(SO4)} are dissolved in water at 298 K. A $0.1 \text{ M}$ aqueous solution of isomer P produces a dense white precipitate upon treatment with excess \ce{BaCl2(aq)}, whereas isomer Q produces no precipitate under identical conditions. The standard reduction potentials ($E^\circ$) for the \ce{Co^{III}} / \ce{Co^{II}} redox couple of the complex cations in these two isomers are experimentally determined to be $+0.22 \text{ V}$ and $+0.75 \text{ V}$ (not necessarily in that order). Based on Crystal Field Theory and the thermodynamic stability of the coordination spheres, identify the correct $E^\circ$ values for isomers P and Q respectively.