Difference Between Carbon Dioxide and Carbon Monoxide


Carbon Monoxide and Carbon Dioxide

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Carbon Dioxide

A colourless gas with a weight of about 53 percent greater than that of dry air is carbon dioxide. The molecules of carbon dioxide carry a covalently double-bonded carbon atom to two atoms of oxygen. In the Earth's atmosphere, it exists naturally as a trace gas. The present concentration is approximately 0.04 percent by volume (412 ppm), having increased by 280 ppm from pre-industrial levels.

Natural sources comprise hot springs, volcanoes, and geysers, and as they are dissolved in water and acids, they are freed from carbonate rocks. It exists naturally in rivers and lakes, groundwater, glaciers, ice caps, and seawater, as carbon dioxide is water-soluble. It is found in petroleum and natural gas deposits.

Carbon Monoxide

Carbon monoxide (CO) is a flammable gas that is colourless, tasteless and odourless and is significantly less dense than air. This gas is toxic to animals which use haemoglobin as a carrier of oxygen (both vertebrates and invertebrates) when it is present at concentrations above approximately 35 ppm. Moreover, it is also released in small amounts during normal animal metabolism and is considered to have certain normal biological functions. It is spatially variable and has a short lifespan in the atmosphere, playing a role in creating ground-level ozone.

Carbon monoxide comprises a single atom of both carbon and oxygen, and these molecules are linked by a triple bond consisting of a net of two pi bonds and a sigma bond. As compared to other triply-bonded diatomic compounds that carry 10 valence electrons, namely cyanide anion, boron monofluoride, nitrosonium cation, and molecular nitrogen, it is the simplest oxocarbon and also is isoelectronic. The carbon monoxide ligand is termed carbonyl in coordination complexes.

Carbon Monoxide to Carbon Dioxide

The consequence of complete combustion is carbon dioxide. Total combustion can be defined as a chemical reaction where hydrocarbon reacts with oxygen in order to form carbon dioxide and water. Complete combustion requires a flame often (but not always). 

In comparison, carbon monoxide is the product of incomplete combustion. If there is a small supply of air, incomplete combustion would occur, but only half quite enough oxygen is added to the carbon, producing carbon monoxide. Carbon monoxide, unlike carbon dioxide, does not naturally exist in the atmosphere. It is formed by the incomplete burning of natural gas, coal, and oil. In the combustion mixture, low oxygen levels and low temperatures contribute to carbon monoxide.

Difference Between Carbon Monoxide and Carbon Dioxide

The difference between carbon dioxide and monoxide are given below:

Carbon Dioxide

Carbon Monoxide

It is a gas including atoms (two) of oxygen and atom (one) of carbon, emitted by certain activities such as breathing, combustion of fuels, etc. Comparatively, this gas is less toxic.

It is an oxygen atom (one) and carbon atom (one) containing gas, emitted by inadequate burning of solid and is toxic.

The molecular mass of carbon monoxide is 44 g/mol

The molecular mass of carbon monoxide is 28.01 g/mol.

Carbon and oxygen atom bond length is found to be 116.3 pm.

Carbon and oxygen atom bond length is found to be 112.8 pm.

The Bond type is Covalent bond.

The Bond type is Covalent bond as well as coordinate bond collectively termed as a triple covalent bond.

It occurs naturally in the atmosphere

Carbon monoxide does not occur in the atmosphere. 

It is naturally produced by the processes of respiration (humans and animals), combustion of fuels, chemical reactions, fermentation.

It is produced due to incomplete combustion of fossils, coal, oil and natural gas.

Carbon dioxide is a non-flammable gas.

Carbon monoxide is a flammable gas.

It is found to be rarely poisonous.

It tends to cause fatal toxicity.

It causes a direct impact on the respiratory system.

It causes a direct impact on the lungs, central nervous system, and blood.


  • Carbon monoxide is especially harmful since it is odourless, but carbon monoxide sensors may be used to alert residents to rising levels of this toxic gas. 

  • Indoor smoking bans are also contributing to lower levels of carbon monoxide indoors. 

  • To prevent the accumulation of this harmful gas, proper air circulation is necessary.

  • Ensuring that heaters, furnaces and chimneys are properly built and ventilated will also avoid the accumulation of carbon monoxide. 

  • Carbon monoxide may also be created by older vehicles. Leaving a car in a closed garage can lead to potentially lethal carbon monoxide levels; more recently constructed cars do not, however, emit dangerous carbon monoxide levels even in an enclosed room.

FAQ (Frequently Asked Questions)

1. Enlist Some Adverse Health Effects Due to Carbon Monoxide.

Ans. Headache, dizziness, vomiting, and nausea may be caused by breathing CO. You can become unconscious or die if CO levels are high enough. Over long periods of time, exposure to moderate and high levels of CO has also been associated with an increased risk of heart disease. Long-term health complications can be faced by people who survive serious CO poisoning.

2. Name Some of the Greenhouse Gases.

Ans. The main greenhouse gases are:

  • Water vapour

  • Nitrous oxide

  • Carbon dioxide

  • Methane

  • Chlorofluorocarbons

  • Ozone