Assertion: CO & NO both combine with haemoglobin.
Reason: Both have equal affinity for haemoglobin.

Options

A. If both 'A' and 'R' are correct and 'R' is correct reason for 'A'.
B. If both 'A' and 'R' are correct and 'R' is not correct reason for 'A'.
C. If 'A' is true and 'R' is false.
D. If 'A' is false and 'R' are true.

Answer

To analyze the assertion and reason provided in the question, we can break it down step by step:

### Step 1: Understanding the Assertion
The assertion states that both carbon monoxide (CO) and nitric oxide (NO) combine with hemoglobin.

- **Explanation**: This is true. Carbon monoxide binds to hemoglobin to form carboxyhemoglobin, while nitric oxide binds to hemoglobin to form nitrosohemoglobin. Both gases can indeed bind to hemoglobin.

### Step 2: Understanding the Reason
The reason given is that both CO and NO have equal affinity for hemoglobin.

- **Explanation**: This statement is false. In reality, nitric oxide has a higher affinity for hemoglobin compared to carbon monoxide. While CO binds very tightly to hemoglobin, NO binds even more effectively, making the reason incorrect.

### Step 3: Conclusion
Based on the analysis:
- The assertion is true (CO and NO both combine with hemoglobin).
- The reason is false (they do not have equal affinity; NO has a higher affinity).

### Final Answer
The correct option is that the assertion is true and the reason is false.

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