Cupric Oxide

Cupric oxide is an inorganic chemical compound composed of cuprous ion and oxide ion. Cupric cuprous are the two forms of copper ions. Copper exists in two types of oxide, the one is with a higher oxidation state and another one is with a lower oxidation state, cupric oxide and cuprous oxide respectively. 

Cupric Oxide and Cuprous Oxide

The oxides of copper are of two types:

Cupric oxide- It is also known as copper cupric oxide. The oxidation state of copper in this compound is +2. +2 is the highest oxidation state of copper. Generally, in short, you can write it as oxide cupric. It exists in the monoclinic crystal system.

Cuprous oxide- the oxidation state of copper in this compound is +1. +1 is the intermediate oxidation state of copper. It can easily get oxidised or reduced.

The oxides of cupric cuprous are represented as CuO and Cu2O respectively.

Preparation of Cupric Oxide and Cuprous Oxide

Cupric Oxide can be prepared by the following methods:

1. It can be produced by the thermal decomposition of the cupric carbonate.

CuCO3 → CuO + CO2

The thermal decomposition of cupric carbonate forms cupric oxide as a product and carbon dioxide gas as a byproduct. 

2. Another method of Cupric oxide preparation is heating copper in the presence of air at a high temperature (around 300-800 degrees celsius).

Cu + O2 → CuO

3. Heating Copper Nitrate- The nitrate of copper is thermally unstable. On heating copper nitrate at a temperature around 180 degrees celsius. 

2Cu (NO3)2 → 2 CuO + O2 + 4 NO2 (this reaction takes place at a temperature around 180 degrees celsius)

4. Heating Cupric Hydroxide- cupric hydroxide is a thermally unstable compound. It gets easily decomposed into cupric oxide on heating.

Cu(OH)2 → CuO + H2O

Properties of Cupric Oxide

Physical Properties of Cupric Oxide

• Cupric oxide is a black colour compound.

• Cupric oxide exists in powder (amorphous) form.

• The melting point of cupric oxide is 1326 degrees celsius.

• Cupric oxide is insoluble in water.

• Cupric oxide is soluble in ammonium chloride and potassium cyanide.

Chemical Properties of Cupric Oxide

• Cupric acid reacts with strong mineral acids like hydrochloric acid (HCl), sulphuric acid (H2SO4), and nitric acid (HNO3) to form salts.

CuO + HNO3 → Cu (NO3)2 + H2O

CuO + 2HCl → CuCl2 + H2O

CuO + H2SO4 → CuSO4 + H2O

• Cupric oxide reacts with the concentrated base and forms salt.

2KOH + CuO + H2O → K2 [Cu (OH)4]

• Cupric oxide reacts with hydrogen and gets reduced to copper.

CuO + H2 → Cu + H2O

• Cupric oxide reacts with carbon monoxide and forms elemental copper and carbon dioxide.

CuO + CO → Cu + CO2

• Cupric oxide reacts with carbon and forms the elemental form of copper.

2CuO + C → 2Cu + CO2

Uses of Cupric Oxide

• Cupric oxide is used as a pigmenting agent in ceramic compounds. It gives blue, red, green, grey, pink, and black glazes.

• Cupric oxide is widely used in laboratories for the preparation of various copper salts.

• Cupric oxide is used in the manufacture of wood preservatives.

• Cupric oxide is used in the welding process.

• Cupric oxide is used in the manufacture of lithium batteries.

Did You Know?

• Paramelaconite is a copper mineral. In this mineral, copper exists in both +1 and +2 oxidation state.

• Do you think that copper was the first element used by man along with gold and iron?

• Copper is an essential element for the human body.

• Copper is used in alloy formation.

• The blood of octopus contains copper as an oxygen carrier. Therefore, the colour of the blood in them is blue.

• Copper is an essential trace mineral.

• Copper is used as a supplement with iron for the anaemic person.