Q44 / 170 · Manipal (MET) 2021 · Chemistry

The standard reduction potential for $\mathrm{Fe}^{2+} / \mathrm{Fe}$ and $\mathrm{Sn}^{2+} / \mathrm{Sn}$ electrodes are -0.44 and -0.14 volt respectively. For the cell reaction $\mathrm{Fe}^{2+}+\mathrm{Sn} \longrightarrow \mathrm{F}_{\mathrm{e}}+\mathrm{Sn}^{2+}$, the standard emf is

  • A
    +0.30 V
  • B
    -0.58 V
  • C
    +0.58 V
  • Correct answer
    D
    -0.30 V

Solution

For the cell reaction, Fe acts as cathode and Sn as anode Hence, $\begin{aligned} E_{\text {cell }}^{\circ} & =E_{\text {cathode }}^{\circ}-E_{\text {anode }}^{\circ} \\ & =-0.44-(-0.14)=-0.30 \mathrm{~V}\end{aligned}$ The negative emf suggests that the reaction goes spontaneously in reversed direction.

Hence, the correct answer is option: 'D'.

Relevant Questions