Balance the following equations: \[\left( \mathbf{i} \right)\text{ }\mathbf{Fe}\text{ }+{{\mathbf{O}}_{\mathbf{2}}}~\to \text{ }\mathbf{F}{{\mathbf{e}}_{\mathbf{2}}}{{\mathbf{O}}_{\mathbf{3}}}\] \[\left( \mathbf{ii} \right)\text{ }\mathbf{Al}{{\left( \mathbf{OH} \right)}_{\mathbf{3}}}~\to \text{ }\mathbf{A}{{\mathbf{l}}_{\mathbf{2}}}{{\mathbf{O}}_{\mathbf{3}}}~+{{\mathbf{H}}_{\mathbf{2}}}\mathbf{O}\] \[\left( \mathbf{iii} \right)\text{ }\mathbf{N}{{\mathbf{H}}_{\mathbf{3}}}+\text{ }\mathbf{CuO}\text{ }\to \text{ }\mathbf{Cu}\text{ }+{{\mathbf{N}}_{\mathbf{2}}}~+{{\mathbf{H}}_{\mathbf{2}}}\mathbf{O}\]