Q 1 :    

The correct value of cell potential in volt for the reaction that occurs when the following two half-cells are connected, is

Fe(aq)2++2e-Fe(s),  E°=-0.44 V

Cr2O7(aq)2-+14H++6e-2Cr3++7H2O,  E°=+1.33 V                           [2023]
 

  • + 1.77 V

     

  • + 2.65 V

     

  • + 0.01 V

     

  • + 0.89 V

     

(1)

Ecell=Ecathode-Eanode

          =(+1.33)-(-0.44)=+1.77 V



Q 2 :    

The standard electrode potential (E°) values of Al3+/Al, Ag+/Ag, K+/K, and Cr3+/Cr are -1.66 V0.80 V-2.93 V and -0.74 V, respectively. The correct decreasing order of reducing power of the metal is                 [2019]

  • Ag > Cr > Al > K

     

  • K > Al > Cr > Ag

     

  • K > Al > Ag > Cr

     

  • Al > K > Ag > Cr

     

(2)

Higher the value of Ered, stronger is the oxidising power. Thus, the decreasing order of reducing power of the metal is K > Al > Cr > Ag.