What is the oxidation number of nitrogen in nitrous oxide?

The standard electrode potentials at $298 \mathrm{K}$ are given below:

$\mathrm{E}{°}_{{\mathrm{Zn}}^{2+}/\mathrm{Zn}}=-0.76\mathrm{V}, \mathrm{E}{°}_{{\mathrm{Fe}}^{2+}/\mathrm{Fe}}=-0.44\mathrm{V}$

${\mathrm{E}}_{{\mathrm{H}}^{+}/{\mathrm{H}}_2}^{\mathrm{o}} = 0.0\mathrm{V}, {\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}^{\mathrm{o}} =+0.34\mathrm{V}$

Which of the two electrodes should be combined to form a cell having the highest emf? Identify the cathode and the anode and write the cell reaction.

Balance the following equation by the oxidation number method.

${\mathrm{Fe}}^{2+}+{\mathrm{H}}^{+}+{\mathrm{Cr}}_2{O}_7^{2-}⟶{\mathrm{Cr}}^{3+}+{\mathrm{Fe}}^{3+}+{\mathrm{H}}_2\mathrm{O}$

Balance the following equation by the oxidation number method.

${\mathrm{I}}_2 + {\mathrm{NO}}_3^{-}⟶{\mathrm{NO}}_{2 }+ {\mathrm{IO}}_3^{-}$

Balance the following equation by the oxidation number method.

Balance the following equation by the oxidation number method.