Identify incorrect statements
A) Pure hydrogen is obtained by the electrolysis of Ba(OH)₂ solution using Nickel electrodes.
B) $\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)\stackrel{1273\mathrm{K}}{\to }\mathrm{CO}\left(\mathrm{g}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$  is called water gas shift reaction
C) $\mathrm{Cu}+2{\mathrm{H}}^{+}\to {\mathrm{Cu}}^{2+}+{\mathrm{H}}_2$ is useful method to prepare hydrogen
D) ${\mathrm{CH}}_2={\mathrm{CH}}_2+\mathrm{CO}+{\mathrm{H}}_2\stackrel{\mathrm{Catalyst}}{\to }{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CHO}$ is called hydro formylation