To solve the given assertion and reason question, let's break it down step by step.
### Step 1: Analyze the Assertion (A)
The assertion states that the weight of one molecule of \( O_2 \) is 32 u (atomic mass units).
- **Explanation**:
- Oxygen (O) has an atomic mass of approximately 16 u.
- Since \( O_2 \) consists of two oxygen atoms, the molecular weight of \( O_2 \) is calculated as:
\[
\text{Molecular weight of } O_2 = 16 \, \text{u} + 16 \, \text{u} = 32 \, \text{u}
\]
- Therefore, the assertion is **true**.
### Step 2: Analyze the Reason (R)
The reason states that 1 gram molecule of \( O_2 \) equals \( 6.023 \times 10^{23} \) molecules.
- **Explanation**:
- The term "gram molecule" is equivalent to "mole".
- By definition, 1 mole of any substance contains \( 6.022 \times 10^{23} \) entities (atoms, molecules, etc.), which is known as Avogadro's number.
- Thus, 1 gram molecule of \( O_2 \) indeed corresponds to 1 mole of \( O_2 \), which contains \( 6.022 \times 10^{23} \) molecules.
- Therefore, the reason is also **true**.
### Step 3: Determine the Relationship Between Assertion and Reason
Now we need to assess whether the reason correctly explains the assertion.
- The assertion is about the molecular weight of \( O_2 \), while the reason discusses the number of molecules in a mole.
- Although both statements are true, the reason does not provide a correct explanation for the assertion regarding the weight of one molecule of \( O_2 \).
### Conclusion
- Assertion (A) is true.
- Reason (R) is true, but it does not explain assertion (A).
Thus, the correct answer is that the assertion is true, the reason is true, but the reason does not explain the assertion.
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