Inhalation of carbon monoxide may cause death because

Options

A. it produces poisonous `HCN` inside the body
B. it damages proteins of the body by cleaving peptide bonds
C. it combines with the iron in hemoglobin and blocks the intake of oxygen by blood.
D. it burns the lungs inside

Answer

C

Explanation

`CO` is very poisonous because it has a `300 `- fold greater affinity for blood hemoglobin than does oxygen:
Hemoglobin + `CO rarr` Carboxyhemoglobin
`"Hemoglobin"+O_(2)underset(larr)(rarr)"Oxyhemoglobin"`
Thus, quite low concentrations of `CO` in air are sufficient to prevent oxygen absorption in the lungs. Without a continuous supply of oxygen, the brain loses consciousness and death follows (due to asphyxiation) unless the supply of oxygenated hemoglobin is restored.