What is standard potential of the Tl3+/Tl electrode? Tl3+ + 2e->Tl+ E =1.26V Tl+ + e->Tl E=-0.336 Tl3+ + 3e->Tl

Dear student ,



   given that ; Ti³⁺ + 2e^-  $\to$Ti⁺ ; E⁰ = 1.26 V -----(i)
                       Ti⁺ + e^-   $\to$ Ti  ;  E⁰ = - 0.336 V-----(ii)
                       Ti³⁺ + 3e^-  $\to$ Ti ; E⁰ =  ?  ------(iii)
   now from the relation $∆$G⁰ = - nFE⁰ 
            from the aove eq. it is clear that eq. (iii) we will get by adding the first and second but emf of the electrode is not additive while the free energies are additive . then on determining the free energies of the above three eq. we get;
      $∆$G⁰₁ = - 2$\times$1.26  $\times$F    ;  $∆$G⁰₂ = - 1$\times$(-0.336) F and   $∆$G⁰₃ = - 3$\times$E⁰₃$\times$F
       from the above eq.  ; $∆$G⁰₃ = $∆$G⁰₁ + $∆$G⁰₂ 
                                - 3$\times$E⁰₃$\times$F = - 2$\times$1.26  $\times$F + { - 1$\times$(-0.336) F }
                                             E⁰₃ = 0.728 V
  Regards