Answer:
The right alternative is Option D (0.78 V).
Explanation:
According to the question,
The cell potential will be:
= [tex]E^0_{Cr_2 O_7/er^{3+}}- E^0_{Fe^{2+}/Fe}[/tex]
By putting the values, we get
= [tex]1.23-0.45[/tex]
= [tex]0.78 \ V[/tex]
Thus the above is the correct option.