E 1 , E 2 and E 3 are the emf of the following three galvanic cells respectively (i) Zn s Zn 2 + 0 . 1 M Cu 2 + 1 M Cu s (ii) Zn s Zn 2 + 1 M Cu 2 + 1 M Cu s (iii) Zn s Zn 2 + 1 M Cu 2 + 0 . 1 M Cu s Which of the following is true?

Step-by-step solution

Key-idea Use Nernst equation, i.e. E emf = E ° cell - 0 . 0591 2 log Zn 2 + Cu 2 + For reaction i E 1 = E ° cell - 0 . 0591 2 log 0 . 1 1 E 1 = E ° cell + 0 . 0591 2 For reaction ii E 2 = E ° cell - 0 . 0591 2 log 1 1 = 0 E 2 = E ° cell For reaction iii E 3 = E ° cell - 0 . 0591 2 log 1 0 . 1 E 3 = E ° cell - 0 . 0591 2 Hence, E 1 > E 2 > E 3 .