Single Choice

Consider the following relations for emf of an electrochemical cell : (i) EMF of cell = (Oxidation potential of anode) - (Reduction potential of cathode) (ii) EMF of cell = (Oxidation potential of anode) + (Reduction potential of cathode) (iii) EMF of cell = (Reduction potential of anode) + (Reduction potential of cathode) (iv) EMF of cell = (Oxidation potential of anode) - (Oxidation potential of cathode) Which of the above relation(s) is correct?

A(iii) and (i)
B(i) and (ii)
C(iii) and (iv)
D(ii) and (iv)
Correct Answer

Solution

The EMF of a cell is given by the following expressions:

EMF of a cell = Reduction potential of cathode - Reduction potential of anode

= Reduction potential of cathode + Oxidation potential of anode

= Oxidation potential of anode - Oxidation potential of cathode

Hence, the relations (ii) and (iv) are correct.

Hence, the correct option is D.

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