This about carbon monoxide is incorrect

The correct option is: "The carboxyhaemoglobin (haemoglobin found to CO) is less stable than oxyhaemoglobin".

Let us break down why this statement about carbon monoxide is incorrect, and examine the chemistry behind carbon monoxide poisoning step-by-step:
1. Incomplete Combustion: Carbon monoxide (CO) is indeed produced during the incomplete combustion of carbon-containing fuels (like wood, coal, or gasoline) when oxygen supply is limited.
2. Affinity for Haemoglobin: When inhaled, carbon monoxide binds to haemoglobin in the red blood cells. The affinity of haemoglobin for carbon monoxide is about 200 to 250 times higher than its affinity for oxygen. This binding forms a stable complex called carboxyhaemoglobin.
3. Stability of the Complex: Because carbon monoxide binds so tightly to haemoglobin, the carboxyhaemoglobin complex is actually much more stable (about 250 times more stable) than the oxyhaemoglobin complex (which is the temporary association of oxygen and haemoglobin). Due to its high stability, it does not easily dissociate to release oxygen.
4. Oxygen Transport Blockage: Once carboxyhaemoglobin is formed, those haemoglobin molecules are no longer available to carry oxygen to vital tissues and organs. This drastically reduces the oxygen-carrying ability of the blood, leading to oxygen deprivation (hypoxia) in body tissues.

Therefore, the statement claiming that carboxyhaemoglobin is less stable than oxyhaemoglobin is false, making it the correct choice for this question.