Among carbon monoxide (CO ) and carbon-dioxide (`CO_(2)`) which is more dangerous? Why ?

Explanation

(i) CO is more dangerous than `CO_(2)`. CO is a poisonous gas.
(ii) CO bind with haemoglobin and forms carboxy haemoglobin complex which is 300 times stable than oxyhaemoglobin complex.
(iii) When the concentration of carboxy haemoglobin reach 3-4%. The oxygen carrying capacity of blood is reduced.
(iv) This results in head ache, nervousness and cardiovascular disorder.