why in this question Fe is taken as anode and zinc as cathode whereas according to electrochemical series Fe lies below zinc??? Also mention the soln for the above ques

Asked by ayushi | 7th Jul, 2016, 04:25: PM

Expert Answer:

According to given reaction, anode is zinc where oxidation takes place and cathode is Fe wher reduction takes place.
We have to reverse both half cell reactions as oxidation potentials are given.
Hence,
Zn2+ (aq) + 2e-  → Zn(s) ,  Eº = -0.76 V
Fe2+(aq) + 2e- → Fe(s) ,  Eº = -0.44 V
Half cell reaction with more positive reduction potential will reverse the half cell reaction with less positive reduction potential.
Hence emf of the cell is,
Eº (RHS) - Eº (LHS) = Eº(cell)
-0.76 V - (- 0.44 V) = 0.32 V
Thus, option (b) is the correct option. 

Answered by Prachi Sawant | 8th Jul, 2016, 03:43: PM