Q. Is CuO(H2) → Cu(H2O) a redox reaction

Yes, the reaction CuO + H2 → Cu + H2O is definitely a redox reaction, involving the transfer of electrons between copper and hydrogen. In this reaction, copper is reduced—it goes from a +2 oxidation state in copper(II) oxide (CuO) to 0 in elemental copper metal (Cu)—meaning it gains electrons. Simultaneously, hydrogen is oxidized—it goes from 0 in H2 gas to +1 in water (H2O)—meaning it loses electrons. This electron transfer is the defining characteristic of all redox reactions.

This reaction is commonly used as a demonstration of redox chemistry and metal reduction in laboratory settings. Hydrogen gas acts as a reducing agent (it causes the reduction of copper by donating electrons) while being oxidized itself, and copper oxide acts as an oxidizing agent (it causes the oxidation of hydrogen by accepting electrons) while being reduced itself. The reaction is practical for extracting copper metal from its oxide and illustrates the principle behind using hydrogen as a reducing agent in metallurgy. Both the change in oxidation states and the physical transformation from black copper oxide powder to reddish-brown metallic copper provide clear evidence that this is a redox reaction, distinguishing it from reaction types like acid-base neutralization or precipitation where no electron transfer occurs.