The standard electrode potentials (reduction) of Pt/Fe³⁺, Fe⁺² and Pt/Sn⁴⁺, Sn⁺² are +0.77 V and 0.15 V

respectively at 25°C. The standard EMF of the reaction

$Sn^{4+} + 2Fe^{2+} \rightarrow Sn^{2+} + 2Fe^{3+}$ is

0.62 V

The correct answer is option 1. 0.62 V

To determine the standard EMF of the reaction $\text{Sn}^{4+} + 2\text{Fe}^{2+} \rightarrow \text{Sn}^{2+} + 2\text{Fe}^{3+}$, we can use the standard electrode potentials and the Nernst equation.

Given:
Standard electrode potential (reduction) of Pt/Fe$^{3+}$, Fe$^{2+}$ ($E^\circ(\text{Pt/Fe}^{3+}, \text{Fe}^{2+}$)) = +0.77 V
Standard electrode potential (reduction) of Pt/Sn$^{4+}$, Sn$^{2+}$ ($E^\circ(\text{Pt/Sn}^{4+}, \text{Sn}^{2+}$)) = 0.15 V

The standard EMF ($E^\circ$) of the reaction can be calculated by subtracting the standard electrode potential of the reactants from the standard electrode potential of the products: $E^\circ = E^\circ(\text{Pt/Sn}^{4+}, \text{Sn}^{2+}) - E^\circ(\text{Pt/Fe}^{3+}, \text{Fe}^{2+})$

$E^\circ = 0.15 \, \text{V} - (+0.77 \, \text{V})$

$E^\circ = -0.62 \, \text{V}$

Therefore, the standard EMF of the reaction $\text{Sn}^{4+} + 2\text{Fe}^{2+} \rightarrow \text{Sn}^{2+} + 2\text{Fe}^{3+}$ is (1) $-0.62 \, \text{V}$.