Assertion (A): Calmel is a chemical compound whereas brass is a mixture.
Reason (R ): Calomel always contains 5.6 times as much mercury as chlorine by weight. Brass can be made with widely different ratios of copper and zine.

Options

A. If both (A) and (R ) are correct and (R ) is the correct explantion for (A)
B. If both (A) and (R ) are correct but (R ) is not the correct explantion for (A)
C. If (A) is correct but (R ) is incorrect.
D. If (A) and (R ) are incorrect.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states that "Calomel is a chemical compound whereas brass is a mixture."

- **Calomel** is a chemical compound with the formula \( \text{Hg}_2\text{Cl}_2 \) (mercury(I) chloride).
- **Brass** is an alloy, which is a mixture of copper and zinc.

**Conclusion from Step 1**: The assertion is true.

### Step 2: Understanding the Reason
The reason states that "Calomel always contains 5.6 times as much mercury as chlorine by weight."

- To verify this, we calculate the weight ratio of mercury to chlorine in calomel.
- The atomic weight of mercury (Hg) is approximately 200.5 g/mol, and that of chlorine (Cl) is approximately 35.5 g/mol.
- In calomel, there are 2 mercury atoms and 2 chlorine atoms. Therefore, the total weight of mercury in calomel is \( 2 \times 200.5 = 401 \) g, and the total weight of chlorine is \( 2 \times 35.5 = 71 \) g.
- The ratio of the weight of mercury to the weight of chlorine is:
\[ \text{Weight ratio} = \frac{401}{71} \approx 5.63 \]
This confirms that calomel contains approximately 5.6 times as much mercury as chlorine by weight.

**Conclusion from Step 2**: The reason is also true.

### Step 3: Relationship Between Assertion and Reason
Since both the assertion and the reason are true, we need to determine if the reason correctly explains the assertion.

- The assertion is about the classification of calomel as a compound and brass as a mixture.
- The reason provides a specific quantitative relationship in calomel that supports its classification as a compound.

**Final Conclusion**: Both the assertion and the reason are true, and the reason is a correct explanation for the assertion.

### Final Answer
Both the assertion (A) and the reason (R) are correct, and the reason is a correct explanation of the assertion.

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