Question

Dry hydrogen can oxidize copper oxide to form copper metal.
A. True
B. False

Answer 1

Hint: Hydrogen has the ability to remove oxygen from many metal oxides, therefore acts as a good reducing agent when heated. In this case, we will be dealing with an example of redox reaction.

Complete step by step solution:

Redox reactions are reactions in which one species is reduced while the other is oxidized in which the oxidation states of the species changes ultimately.

In the question, dry hydrogen reacts with copper oxide, oxygen is removed from the copper oxide and it gets reduced. In other words, Cu goes from +2 oxidation state as a reactant to a state of 0 as a final product. Hence, CuO is the oxidizing agent. It oxidizes the dry hydrogen and accepts its electrons. On the other hand, the dry hydrogen is oxidized as it goes from 0 oxidation state as a reactant to a state of +1 as a product. In this reaction dry hydrogen acts as a reducing agent. It reduces the other reactant, CuO by donating an electron to it. All over, Copper will gain 2 electrons and each hydrogen atom will lose 1 electron.

\[\dfrac{\begin{align}
  & \text{Reduction}\overset{+2}{\mathop{\text{Cu}}}\,\overset{-2}{\mathop{\text{O}}}\,\,\text{+}\,\text{2}{{\text{e}}^{-}}\,\to \,\overset{0}{\mathop{\text{Cu}}}\,\text{ + }\overset{-2}{\mathop{{{\text{O}}^{2-}}}}\, \\
 & \text{Oxidation}{{\overset{0}{\mathop{\text{H}}}\,}_{2}}\,+\,\overset{-2}{\mathop{{{\text{O}}^{2-}}}}\,\,\,\,\,\,\to \,{{\overset{+1}{\mathop{\text{H}}}\,}_{2}}\overset{-2}{\mathop{\text{O}}}\,\text{ + 2}{{\text{e}}^{-}} \\
\end{align}}{\operatorname{Re}\text{dox reaction CuO + }{{\text{H}}_{2}}\,\to \,\text{ Cu + }{{\text{H}}_{2}}\text{O }}\]

Therefore, it’s true, dry hydrogen can oxidize copper oxide to form copper metal.

Note: Don’t get confused after seeing dry hydrogen. It is essentially hydrogen gas with no trace of water molecules or moisture present in it. As we increase the temperature, his reaction occurs very quickly.