One of the products of burning of coal is a toxic gas 'A'. The gas A combines with the haemoglobin to form a compound 'B'. Concentration of A greater than 750 ppm leads to disease called 'C' in human beings. However, the patient suffering from C' can be treated in a high pressure chamber containing gas 'D'. The main product formed on keeping in gas 'D' is the product E which helps the person to recovery. What are A, B, C, D and E? Write the reactions involved.

Explanation

A= Carbon monoxide (CO)
B=Carboxyhaemoglobin (HbCO)
C = Anoxia or Asphyxiation
D=Oxygen `(O_2)`
E = Oxyhaemoglobin `(HbO_2)`
Reaction. `C+1/2O_2 to CO`
`Hb+CO to underset"Carboxyhaemoglobin""HbCO"`
`HbCO+O_2 to underset"Oxyhaemoglobin"(HbO_2)+CO`