Carbon Monoxide

Carbon monoxide is formed by the incomplete oxidation of carbon. It is found in petrol fumes.


Lab method

1.        Concentrated sulphuric acid is added to oxalic acid and heated. Dehydration occurs, and a mixture of carbon dioxide and carbon monoxide is formed.
Carbon monoxide is collected by the downward placement of water.
H2C2O4 Δ (Conc. H2SO4) H2O + CO2 + CO 
Carbon dioxide is absorbed by potassium hydroxide solution.

2.         Concentrated sulphuric acid is added to formic acid and heated. Dehydration occurs, and the carbon monoxide formed is collected over water.
H · COOH Δ (Conc. H2SO4) H2O + CO

Sodium formate can also be used – first formic acid is liberated, then it is dehydrated
H · COONa + H2SO4 NaHSO4 + H · COOH
H · COOH Δ (Conc. H2SO4) H2O + CO

These preparations should be carried out in fume cupboards.



  1. It is a colorless, odorless and tasteless gas.
  2. It is slightly soluble in water.
  3. It is highly poisonous.
  4. Boiling point -192°C
  5. Melting point -207°C


  1. It is a neutral oxide of carbon.
  2. It is a stable compound.
  3. It does not support combustion, but is combustible.
               2CO + O2 2CO2 + 135400 cal.
  1. It reduces metal oxides at high temperatures.
               PbO + CO Pb + CO2
               CuO  + CO Cu + CO2
               Fe2O3 + 3CO 2Fe + 3CO2
  1. It combines with chlorine in sunlight and in the presence of charcoal.
               CO + Cl2 COCl2 carbonylchloride (phosgene)
  1. At 200°C and 6-10 atmos. it combines with sodium hydroxide.
               NaOH + CO H · COONa
  1. It forms an addition product with copper (I) chloride in HCl or ammonia solution.
               CuCl + CO + 2H2O CuCl · CO · 2H2O
    1. With hydrogen, at 300°C, and over nickel, it forms methane.
  300°C, Ni
                                 CO + 3H2  CH4 + H2O
    1. With hydrogen, at 400°C, and zinc and chromium oxides it forms methyl alcohol.
                              CO + 2H2  CH3OH


  1. As a fuel – producer of water gas
  2. To manufacture phosgene, sodium formate, and methyl alcohol

Drying Apparatus

Efflorescent, Deliquescent, and Hygroscopic Substances

1.      In efflorescence, the vapor pressure of the hydrated salt is greater than the vapor pressure of water vapor in the atmosphere. The salt tries to equalize pressure but, in view of the size of the atmosphere, this can never be achieved, and so it passed to a lower hydrate or the anhydrous salt, with a lower vapor pressure.
Na2CO3 · 10H2O Na2CO3 · H2O + 9H2O
2.      In deliquescence, the vapor of the salt hydrate (and its saturated solution) is less than the vapor pressure of water vapor in the atmosphere. The salt tries to equalize pressures by absorbing water from the atmosphere, forming eventually an unsaturated solution.
MgCl2, 6 H2O, P2O5, NaOH
It should be remembered that the water vapor present in the atmosphere is not constant, varying from day to day and especially from summer to winter. Hence, there is a possibility that certain compounds may be either efflorescent or deliquescent depending on the season or the locality.
Ordinary common salt is not deliquescent but because of MgCl2 which is an impurity, it dissolves and forms a solution in rainy reason and becomes deliquescent.
Calcium chloride is sprinkled on the road to remove dust as it absorbs moisture and forms a saturated solution by dissolving in it. It is used as a dehydrating agent. The term deliquescent is used for solids only.
3.      A hygroscopic substance (e.g. conc. H2SO4, CuO) absorbs water from the atmosphere without forming a solution.
Human hair is hygroscopic.
H2SO4 is not deliquescent but it is hygroscopic and used as a dehydrating agent.

Drying Apparatus

To Dry
Drying Agent
·            Conc. H2SO4
·        P2O5
·        CaCl2
Woulfe’s bottle
·        P2O5
·            CaCl2
·        CaO
Drying Tower
·        (Salt and ice) Freezing mixture
U tube
·        Conc. H2SO4
·        Silica gel
·        CaO
·        Anhydrous CaCl2
·        Conc. H2SO4


A solid bounded by plain surfaces having definite geometrical shapes. In nature, crystals are found as minerals, for example, ruby, diamond, graphite, etc. These crystals have beautiful color due to impurities or traces of water present in them.

Making Crystals

1.           Dissolving a solid in water or any other solvent and then evaporating the liquid. For example, salt, nitre, alum in water. Sulfur in carbon disulphide or carbon tetrachloride CCl4, iodine in petrol or benzene or spirit.
2.           By melting a solid and allowing it to cool properly. For example, prismatic sulfur.
3.           By sublimation. For example, iodine and ammonium crystals.
4.           By subjecting a solid to great heat and pressure. For example, diamond and graphite. The cost is prohibitive as artificial diamond is more costly than natural diamond.

Water of Crystallization

Some solids while crystallizing out from solution unite with a definite quantity of H2O known as water of crystallization/ hydration. This water of crystallization can be driven out by heating the crystal to 100°C, and may be condensed and tested. Such crystals lose their crystalline structure and become anhydrous.

Water of crystallization is the number of molecules of water combined it a loose chemical combination which on heating on exposure to air is partly on fully given off by a hydrated salt.

Hydrated Salts

A hydrated salt is a substance which contains water of crystallization which on exposure to air or heat becomes anhydrous by giving off partly or fully its water of crystallization.

Hydrated Salt
Chemical Formula
Common Name
sodium carbonate
Na2CO3 · 10H2
washing soda
sodium sulphate
Na2SO4 · 10H2
Glauber’s salt
copper sulphate
CuSO4 · 5H2
blue vitriol
ferrous sulphate
FeSO4 · 7H2
green vitriol
zinc sulphate
ZnSO4 · 7H2
white vitriol (H2SO4 is called oil of vitriol)
cobalt chloride
CoCl2 · 6H2O

barium chloride
BaCl2 · 2H2O

calcium chloride
CaCl2 · 6H2O

magnesium sulphate
MgSO4 · 7H2
Epsom salt

Crystals without Water of Crystallization – Anhydrous

Anhydrous Salt
Chemical Formula
sodium chloride (common salt)
potassium chromate  
potassium chloride