Carbon Monoxide

What is Carbon Monoxide?

Carbon monoxide is an organic dative covalent compound with the formula CO. It is produced at large scale industrially as it is used for manufacturing numerous organic and inorganic compounds. It is flammable and toxic gas so it must be handled very carefully. 


Greek philosopher Aristotle was the first who observed or recorded that coal produces carbon monoxide on burning. Then in 1776, French Chemist de Lassone produced carbon monoxide. He heated zinc oxide (ZnO) with coke to produce CO. But as CO burned with blue flame so by mistake, he concluded that the gas is hydrogen. Although soon in 1800, Scottish Chemist William Cruickshank identified that the gas is not hydrogen instead it is a compound of carbon and oxygen.  


Structure of Carbon Monoxide or CO

Molecular formula of carbon monoxide is CO. Its structural formula is given as –

: C ☰ O : 


One molecule of carbon monoxide consists of one carbon and one oxygen atom which are joined by two pi bonds and one sigma bond. Carbon atom has 4 valence electrons and oxygen atom has 6 valence electrons, thus in total carbon and oxygen have 10 electrons in valence shell in one molecule of carbon monoxide. So, triple bonds are formed following the octet rule for both the atoms. Carbon has sp hybridization in carbon monoxide. Bond angle is 180°. Its bond length is 112.8 pm.  


Properties of Carbon Monoxide 

Carbon monoxide shows following physical and chemical properties –

  • Molecular weight of carbon monoxide (CO) is 28g.

  • It is an odorless, colorless and tasteless gas. 

  • It is highly toxic in nature.

  • It is flammable. 

  • Its melting point is -205 .

  • Boiling point of CO is -191.5 .

  • It is very less soluble in water. Only 25mg of CO is soluble in one liter of water at 25

  • It is soluble in chloroform, acetic acid, ethyl acetate, ethanol, ammonium hydroxide and benzene. 

  • Carbon monoxide has polar covalent bonds. 

  • It is used as a ligand in many coordination complexes. 

  • Reaction with chlorine – Carbon monoxide reacts with chlorine and forms COCl2. Reaction is given below –

CO + Cl2 🡪 COCl2

  • Reaction with iron(III) oxide – Carbon monoxide is used as a reducing agent in blast furnaces for extraction of iron from its ore. Reaction is given below –

Fe2O3 + 3CO 🡪 2Fe + 3CO2

  • Reaction with copper oxide – Carbon monoxide reacts with copper oxide and forms copper and carbon dioxide. Reaction is given below –

CuO + CO 🡪 Cu + CO2

  • Reaction with nickel – Carbon monoxide reacts with nickel and forms tetracarbonyl nickel. It is a very toxic compound which has a musty smell. Reaction is given below –

Ni + 4CO 🡪 Ni(CO)4

  • Reaction with water vapor – Carbon monoxide reacts with water at a very high temperature and gives CO2 and H2. Reaction is given below –

CO + H2O(g) 🡪 CO2 + H2

  • Reaction with hemoglobin – Carbon monoxide binds with hemoglobin. This is a reason for the death of human beings due to inhalation of carbon monoxide in excess. Reaction is given below –

Hgb + CO 🡪 HgbCO

Iron present in hemoglobin binds with CO very strongly. 


Production of Carbon Monoxide 

Carbon monoxide is prepared in laboratories and its large - scale production is done in industries. We will discuss its laboratory methods of production and industrial methods of production separately. Let us first discuss its laboratory methods of preparation –

From zinc and calcium carbonate – On heating powdered zinc and calcium carbonate mixture, we get zinc oxide, calcium oxide and carbon monoxide. The reaction is given below –

Zn + CaCO3 🡪 ZnO + CaO + CO


From silver nitrate and iodoform – Reaction of silver nitrate and iodoform also gives carbon monoxide. Reaction is given below –

CHI3 + 3AgNO3 + H2O 🡪 3HNO3 + CO + 3AgI


By dehydration of methanoic acid – On dehydration of methanoic acid in presence of conc. Sulfuric acid gives carbon monoxide. Reaction is given below –

HCOOH 🡪 CO + H2O


Now let’s discuss industrial methods of production of carbon monoxide –

From carbon – In industries, the main source of carbon monoxide is producer gas. Producer gas is a mixture of carbon monoxide and nitrogen. It is produced from coke. Air is passed over red – hot carbonaceous fuel or coke and carbon monoxide is formed. It is an exothermic reaction. The reactions involve in the process are given below –

C + O2 → CO2 +97,600 calories

CO2 + C → 2CO, –38,800 calories

2C + O2 → 2CO +58,800 calories

Water gas – Another source of carbon monoxide is water gas. It is produced by the reaction of steam and carbon. It is an endothermic process. Reaction is given below –

H2O + C 🡪 H2 + CO 


Uses of CO (Carbon Monoxide)

Its large - scale production at industrial level clearly indicates its importance in various fields. Few of its uses are listed below –

  • It is used as one of the reagents for production of aldehydes. 

  • It is used in the manufacturing of detergents. 

  • Phosgene is produced by using carbon monoxide. 

  • It is used in purification of nickel.

  • It is used in water gas shift reactions to produce hydrogen.

  • It is used in meat coloring.

  • It is used as a reducing agent. 

  • It is used in many beverages.

  • It is used in high powered infrared lasers and removal of rust from the surface of metals. 

  • It is used in metallurgy.

  • It has been proposed that it can be used as fuel on Mars. 


Toxicity of Carbon Monoxide 

CO is very poisonous gas. When it is inhaled in large quantities, it can be lethal. As it reacts with iron of hemoglobin and forms carboxyhemoglobin in the blood. Mining workers are generally at high risk of carbon monoxide toxicity. Heart patients, smokers, diabetic patients are also at high risk of CO toxicity. Symptoms of CO poisoning are headache, vomiting, chest pain, dizziness etc. 


This ends our coverage on the topic “Carbon monoxide”. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to solve problems based on the topic. If you are looking for solutions of NCERT Textbook problems based on this topic, then log on to Vedantu website or download Vedantu Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.