GS Environment

The poisonous nature of carbon monoxide (CO) is due to its

  1. insolubility in water
  2. ability to form a complex with haemoglobin
  3. ability to reduce some metal oxides
  4. property of having one sigma bond


Carbon monoxide is poisonous. It binds to haemoglobin to form carboxyhaemoglobin, which is about 300 times more stable than the oxygen-haemoglobin complex.

In blood, when the concentration of carboxyhaemoglobin reaches about 3 to 4 per cent, the oxygen carrying capacity of blood is greatly reduced. This oxygen deficiency, results into headache, weak eyesight, nervousness and cardiovascular disorder. This is the reason why people are advised not to smoke.

The correct option is B.