Introduction

Carbon forms two important oxides, namely  carbon (iv) oxide and carbon (ii) oxide. The atmosphere contains about 0.03% by volume of carbon(iv) oxide. A small percentage of carbon (iv) oxide is found in the dissolved form of water. In the combined form, it is found mainly as metallic trioxocarbonates(iv) and hydrogen trioxocarbonates (iv) in the earth’s crust.

Carbon (ii) Oxide

Carbon (II) oxide, also known as carbon monoxide, exhibits oxidation state of +2. It is the choking gas produced during the incomplete combustion of gasoline in car engines. Carbon monoxide is a colourless, odourless, and tasteless gas that is slightly less dense than air.

Laboratory Preparation of Carbon (II) Oxide

Carbon (II) oxide (carbon monoxide), CO, is prepared in the laboratory by dehydrating methanoic acid (formic acid), HCOOH or ethanedioic (oxalic) acid and passing carbon(IV) oxide, CO₂, through red-hot carbon.

Dehydration

Methanoic acid, COOH, dehydrated in the presence of a dehydrating agent, concentrated tetraoxosulphate(VI) acid, H₂SO₄.

HCOOH(l) + conc. H₂SO₄ → CO(g) + H₂O(g)

Ethanedioic acid is heated warmly with concentrated tetraoxosulphate(VI) acid to form a gaseous mixture containing equal volume of carbon(II) oxide and carbon(IV) oxide. The mixture is passed through concentrated sodium hydroxide to separate the carbon(IV) oxide, thus forming carbon(II) oxide…

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Oxides of Carbon