Dihydrogen of high purity $\left(>99.95 \%\right)$ is obtained through :

The equation that represents the water-gas shift reaction is :

Consider the following equations :
$2{\mathrm{Fe}}^{2+}+{\mathrm{H}}_2{\mathrm{O}}_2\to \mathrm{xA}+\mathrm{yB}$

(in basic medium)

$2{\mathrm{MnO}}_4^{-}+6{\mathrm{H}}^{+}+5{\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{x}}^{\text{'}}\mathrm{C}+{\mathrm{y}}^{\text{'}}\mathrm{D}+{\mathrm{z}}^{\text{'}}\mathrm{E}$

(in acidic medium)

The sum of the stoichiometric coefficients $\mathrm{x},\mathrm{y},{\mathrm{x}}^{\text{'}},{\mathrm{y}}^{\text{'}}$ and ${\mathrm{z}}^{\text{'}}$ for products $\mathrm{A},\mathrm{B},\mathrm{C},\mathrm{D}$ and $\mathrm{E}$ respectively, is _______