(A): Nitrous oxide is called laughing gas.
(R): it is a colourless gas having a faint sweet odour.

Options

A. Both A & R are true, R is the correct explanation of A
B. Both A & R are true, R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true

Answer

To analyze the given statements regarding nitrous oxide (N₂O), we will evaluate both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "Nitrous oxide is called laughing gas."
- This is a well-known fact. Nitrous oxide is commonly referred to as laughing gas due to its euphoric effects when inhaled.

### Step 2: Understand the Reason
The reason states that "it is a colorless gas having a faint sweet odor."
- This is also true. Nitrous oxide is indeed a colorless gas and has a faint sweet smell.

### Step 3: Determine the Relationship
Now we need to determine if the reason provided is a correct explanation for the assertion.
- While both statements are true, the reason does not explain why nitrous oxide is called laughing gas. The name "laughing gas" is derived from the gas's psychoactive effects rather than its physical properties.

### Conclusion
Both the assertion and the reason are true, but the reason does not correctly explain the assertion. Therefore, the correct answer is that both the assertion and reason are true, but the reason is not the correct explanation of the assertion.

### Final Answer
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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