Use standard electrode reduction potentials to calculate the standard state voltage for

Cr³⁺ + 3e^- --> Cr

MnO₄^-  + 8H⁺ + 7e^-  - -> Mn + 4H₂O

K_eq for Ag⁺ + 2CN^- - -> Ag(CN)₂^- is 7.08 X 10⁺¹⁹.  Find the standard state potential for

 Ag(CN)₂^- + e^- - -> Ag + 2CN^-

Answers:

-0.74 V

+0.77 V

-0.38 V