Carbon Oxides
Carbon monoxide is a highly poisonous gas; on what basis does it exert its toxic effect on the human body at the molecular level?
Select the correct option:
Solution
It binds strongly to haemoglobin, blocking oxygen transport
The toxicity of carbon monoxide arises from its strong interaction with the oxygen-carrying protein in blood. Carbon monoxide binds to the iron centre of haemoglobin to form carboxyhaemoglobin, and this binding is roughly two hundred times stronger than the binding of oxygen. As a result, carbon monoxide occupies the sites meant for oxygen and prevents haemoglobin from transporting oxygen to the body's tissues, leading to oxygen starvation that can be fatal. The option that it dissolves bones has no basis. The option that it is acidic is incorrect, since carbon monoxide is a neutral oxide. The option that it is radioactive is false. Understanding the physiological toxicity of carbon monoxide in terms of competitive binding to haemoglobin is a standard NCERT environmental and Group 14 point. Plausibility check: the far greater binding affinity of carbon monoxide than oxygen for haemoglobin directly explains why even small concentrations are dangerous, confirming the mechanism.
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About This Question
- Subject
- chemistry
- Chapter
- p-block elements
- Topic
- carbon oxides
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
It binds strongly to haemoglobin, blocking oxygen transport
The toxicity of carbon monoxide arises from its strong interaction with the oxygen-carrying protein in blood. Carbon monoxide binds to the iron centre of haemoglobin to form carboxyhaemoglobin, and this binding is roughly two hundred times stronger than the binding of oxygen. As a result, carbon monoxide occupies the sites meant for oxygen and prevents haemoglobin from transporting oxygen to the body's tissues, leading to oxygen starvation that can be fatal. The option that it dissolves bones has no basis. The option that it is acidic is incorrect, since carbon monoxide is a neutral oxide. The option that it is radioactive is false. Understanding the physiological toxicity of carbon monoxide in terms of competitive binding to haemoglobin is a standard NCERT environmental and Group 14 point. Plausibility check: the far greater binding affinity of carbon monoxide than oxygen for haemoglobin directly explains why even small concentrations are dangerous, confirming the mechanism.
This easy difficulty chemistry question is from the chapter p-block elements, covering the topic of carbon oxides. It appeared in the 2025 exam.
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