Benzene and Oxygen Reaction (Combustion) | C6H6 + O2
Benzene, burns with oxygen gas and heat is released as a result. As chemical products, carbon dioxide and water are given if complete combustion is achieved. Otherwise, carbon monoxide can be given as another product if the supplied oxygen gas amount is not sufficient for a complete combustion.
C6H6 + O2 → CO2 + H2O
In this tutorial, we will discuss followings.
Benzene chemical properties important in combustion procedure
Benzene is an organic compound which contains six carbon atoms and six hydrogen atoms. Benzene burns with a black smoke due to higher carbon percentage.
- Benzene is a colourless liquid at room temperature and volatile.
- Flash point of benzene: -11.630C
- Boiling point: 800C
Stoichiometric balanced chemical reaction of benzene and oxygen gases
Two moles of benzene react with fifteen moles of oxygen gas and produce twelve moles of carbon dioxide and six moles of water.
2C6H6(l) + 15O2(g) → 12CO2(g) + 6H2O(g)
Change of oxidation numbers in benzene combustion
Because, combustion process is a process of redox reactions (oxidation - reduction), oxidation numbers of carbon and oxygen are are changed during the reaction as below.
- In benzene molecule, there are six carbon atoms and all of them exist at same oxidation states (-1). All of those carbon atoms are oxidized to carbon dioxide molecules. In carbon dioxide molecule, carbon is at +4 oxidation state.
- Oxygen is at 0 oxidation state in oxygen molecule (O2) and that those oxygen atoms are reduced to -2 oxidation state.
Thermal energy and heat generation
Standard enthalpy of combustion of benzene (ΔHc0(C6H6,(l))) = -3267.6 kJ mol-1
Health and safety
- Benzene is considered as a Carcinogenic compound.
- Both benzene liquid and vapour is highly flammable.
- Causes skin and eye irritation.
- Can be fatal, if inhaled or swallowed
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