Carbon monoxide was first prepared by Lasson in 1776,by heating zinc oxide with wood charcoal.It was mistaken for hydrogen, because it burnt with a pale blue flame. In 1880,Cruik shank established that carbon monoxide is a compound of carbon and oxygen and not an element hydrogen.

Carbon monoxide - Occurrence around volcanic regions Traces in atmosphere[industrial area] traces in tobacco smoke

Some Basic Features of Carbon monoxide

Preparation of Carbon Monoxide Carbon monoxide was first prepared in the laboratory in 1776 by J.M.F. de Lassone, a French chemist. As carbon monoxide is extremely poisonous, its preparation should be carried out only in a fume chamber. Under no circumstances must the gas be inhaled or smelled.

Preparation of carbon monoxide by dehydrating oxalic acid with hot concentrated sulphuric acid

Preparation of carbon monoxide by dehydrating formic acid

Commercial Preparation of Carbon Monoxide Carbon monoxide is commercially prepared by burning carbon in excess of oxygen, and then passing the carbon dioxide so formed, over white- hot carbon.

Tests for Carbon Monoxide Carbon monoxide is colourless, neutral gas. It burns in air or oxygen with a pale blue flame to form carbon dioxide. Carbon monoxide has no action on limewater, whereas carbon dioxide turns limewater milky. A strip of filter paper, dipped in a solution of palladium chloride turns pink, green or black when exposed to air containing carbon monoxide. The darkness of the colour depends on the concentration of the gas.

Physical Properties of Carbon Monoxide Carbon monoxide is colorless, almost odorless and tasteless gas. Density:It is very slightly lighter than air. Vapor Density=14 [Vapor density of air =14.4]. Solubility:Carbon monoxide is very slightly soluble in water.100 volumes of water can dissolve only 3.5 volumes of the gas at S.T.P Poisonous nature This is a highly poisonous gas. Air containing even less than 1% of carbon monoxide, can be fatal, if breathed in for about 10 to 15 minutes.

Chemical Properties of Carbon Monoxide Carbon monoxide is a neutral oxide. It is neither acidic nor basic. Stability:It is very stable and cannot be decomposed by heat. Combustibility:It is a combustible gas. It burns well in air or oxygen to form carbon dioxide.

This is a highly exothermic reaction. Hence it is a very good fuel.

Combination with chlorine Carbon monoxide combines with chlorine in presence of sunlight and charcoal as catalyst, to form carbonyl chloride, commonly called as phosgene.

Combination with sodium hydroxide Carbon monoxide when heated under a pressure of six atmosphere, combines with sodium hydroxide and flakes to form sodium formate.

Reducing property:Carbon monoxide is a powerful reducing agent. When CO is passed over heated metallic oxides, it takes away the oxygen to form carbon dioxide and reduces the oxides to their respective metals

As a synthetic reagent Carbon monoxide acts as the staring material for the synthesis of many important organic substances. For e.g., the synthesis of methyl alcohol, or methanol, (CH 3 OH) takes place by the reaction of carbon monoxide and hydrogen.

Combination with metals When carbon monoxide is passed over heated metals under pressure, metal carbonyls are formed.

Combination with cuprous chloride Carbon monoxide is absorbed by ammonical cuprous chloride to form an addition compound.

Physiological Action of Carbon Monoxide Carbon monoxide is an extremely poisonous gas. When carbon monoxide is breathed in, it combines with the haemoglobin of the blood, to form a very stable compound, called carboxy haemoglobin. This compound being stable cannot carry oxygen to the cells. As a result, haemoglobin stops functioning as the oxygen carrier. Within a short time, all the haemoglobin becomes carboxy haemoglobin and gets destroyed, resulting in death.