Question

Oxidising agent and reducing agent of copper oxide react with water to form copper and water

Answer 1

2 MnO4-(aq) + 5 H2C2O4(aq) + 6 H+(aq) 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l)

Oxalic acid is oxidized to carbon dioxide in this reaction and the permanganate ion is reduced to the Mn2+ ion.

Oxidation:H2C2O4

CO2+3+4Reduction:MnO4-Mn2++7+2

The permanganate ion removes electrons from oxalic acid molecules and thereby oxidizes the oxalic acid. Thus, the MnO4- ion acts as an oxidizing agent in this reaction. Oxalic acid, on the other hand, is a reducing agent in this reaction. By giving up electrons, it reduces the MnO4- ion to Mn2+.

Atoms, ions, and molecules that have an unusually large affinity for electrons tend to be good oxidizing agents. Elemental fluorine, for example, is the strongest common oxidizing agent. F2 is such a good oxidizing agent that metals, quartz, asbestos, and even water burst into flame in its presence. Other good oxidizing agents include O2, O3, and Cl2, which are the elemental forms of the second and third most electronegative elements, respectively.

Another place to look for good oxidizing agents is among compounds with unusually large oxidation states, such as the permanganate (MnO4-), chromate (CrO42-), and dichromate (Cr2O72-) ions, as well as nitric acid (HNO3), perchloric acid (HClO4), and sulfuric acid (H2SO4). These compounds are strong oxidizing agents because elements become more electronegative as the oxidation states of their atoms increase.

One element gets oxidized and the other gets reduced.

Cu in CuO has a oxidation state of 2+2+ and oxygen in CuO has a oxidation state of 2−2−.

The Cu goes from an oxidation state of 2+2+ as a reactant to a state of 0 as a product.

Hydrogen goes from an oxidation state of 0 as a reactant to a state of 1+1+ as a product.

Copper has gained 2 electrons and each hydrogen atom has lost 1 electron.

so copper has been reduced and hydrogen has been oxidized. The copper acted as an oxidizing agent for the hydrogen and hydrogen acted as a reducing agent for the copper.