Question

The standard reduction potential for `Fe^(2+)//Fe and Sn^(2+)//Sn` electrode are -0.44 and -0.14 volt respectively. For the givencell reaction `Fe^(2+)+SntoFe+Sn^(2+)`, the standard EMF is:-
A. `+0.30V`
B. `-0.58V`
C. `+0.58V`
D. `-0.30V`

Answer 1

Correct Answer - D
For the cell reaction, Fe acts as cathode as Sn as anode. Hence,
`E_(cell)^(o)=E_(cathode)^(o)-E_("anode")^(o)=-0.44-(-0.14)=-0.30V`
the negative EMF suggests that the reaction goes spontaneously in reverse direction.