$\mathrm{EMF}$ of a cell in terms of reduction potential of its left and right electrodes is

Standard electrode potentials of two half cells are given as 

${\mathrm{Zn}}^{2+}|\mathrm{Zn}=-0.76 \mathrm{V};\mathrm{Ag}|\mathrm{Ag}=0.80 \mathrm{V}$

The $\mathrm{emf}$ of the cell $\mathrm{Zn}\left|{\mathrm{Zn}}^{2+}\right(1\mathrm{M})\Vert {\mathrm{Ag}}^{+}|\mathrm{Ag}\left(1\mathrm{M}\right)$ will be

In the electrochemical reaction $2{\mathrm{Fe}}^{3+}+\mathrm{Zn}⟶{\mathrm{Zn}}^{2+}+2{\mathrm{Fe}}^{2+},$ increasing the concentration of ${\mathrm{Fe}}^{2+}$

Consider the following $\mathrm{E}°$ values.

$\mathrm{E}{°}_{{\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}}=+0.77 \mathrm{V}; \mathrm{E}{°}_{{\mathrm{Sn}}^{2+}/\mathrm{Sn}}=-0.14 \mathrm{V}$

Under standard conditions the potential for the reaction.

${\mathrm{Sn}}_{\left(\mathrm{s}\right)}+2{{\mathrm{Fe}}^{3+}}_{\left(\mathrm{aq}\right)}\to 2{{\mathrm{Fe}}^{2+}}_{\left(\mathrm{aq}\right)}+{{\mathrm{Sn}}^{2+}}_{\left(\mathrm{aq}\right)} \text{is}$