Question

The toxic effect of carbon monoxide is due to its greater affinity for haemoglobin as compared to oxygen approximately by

• A. 200 times
• B. 1000 times
• C. 2 times
• D. 20 times.

Answer 1

The correct option is A 200 times

Carbon monoxide combines with Hb far more readily than $O_2$ (CO has about 200 times greater affinity for Hb as compared to $O_2$), forming a relatively stable compound carboxyhaemoglobin. This causes low supply of $O_2$ to the body cells leading to headache, nausea, dizziness, paralysis and even death.