Preparation of carbon monoxide by dehydrating oxalic acid with hot concentrated sulphuric acid
Carbon monoxide is prepared with the help of oxalic acid and concentrated sulphuric acid as shown in figure 11.2.
Oxalic acid has the formula . Sulphuric acid reacts with oxalic acid and removes from it one molecule of water (both the hydrogen atoms, along with an oxygen atom). The product left behind due to this reaction, is a molecule of carbon dioxide and a molecule of carbon monoxide. The carbon dioxide can be removed by passing it through a concentrated solution of potassium hydroxide.
Preparation of carbon monoxide by dehydrating formic acid
Formic acid has the formula HCOOH. Formic acid can also be dehydrated in a similar way by hot concentrated sulphuric acid. Sulphuric acid removes two atoms of hydrogen and one atom of oxygen as a molecule of water from it, and leaves behind one molecule of carbon monoxide (Fig.11.3).
Physical properties of carbon monoxide
Carbon monoxide is colorless, almost odorless and tasteless gas.
It is very slightly lighter than air.Vapor Density=14 [Vapor density of air =14.4].
Carbon monoxide is only very slightly soluble in water.100 volumes of water can dissolve only 3.5 volumes of the gas at S.T.P
d) 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.
It is very stable and cannot be decomposed by heat.
It is a combustible gas. It burns well in air or oxygen to form carbon dioxide. The formation of carbon dioxide is tested by passing it through a solution of lime water. (Fig.11.4).
This is a highly exothermic reaction. Hence it is a very good fuel.
However, it is not a supporter of combustion,
Combination with chlorine
Carbon monoxide combines with chlorine in presence of sunlight and charcoal as catalyst, to form carbonyl chloride, commonly called as phosgene.
e) Combination with sodium hydroxide
Carbon monoxide when heated under a pressure of six atmosphere, combines with sodium hydroxide and flakes to form sodium formate.
f) 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 (Fig.11.5).
g) 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, (CH3OH) takes place by the reaction of carbon monoxide and hydrogen.
h) Combination with metals
When carbon monoxide is passed over heated metals under pressure, metal carbonyls are formed.
i) Combination with cuprous chloride
Carbon monoxide is absorbed by ammonical cuprous chloride to form an addition compound.Uses of carbonmonoxide
2. It is used as a reducing agent in the extraction of metals. Carbon monoxide reduces the metal oxides to metals. Usually coke is used to generate this gas. In this process coke combines with oxygen to form carbon dioxide, which gets reduced to carbon monoxide due to the lack of oxygen.3. Carbon monoxide is used in the manufacture of methyl alcohol, sodium formate, phosgene, etc.