Assertion : Lead, tin and bismuth are purified by liquation method.
Reason : Lead, tin and bismuth have low m.p. as compared to impurities.

Options

A. If both assetion and reason are CORRECT, and reason is the CORRECT explanation of the assertion
B. If both assertion and reason are CORRECT, but reason is NOT the CORRECT explanation of the assertion
C. If assertion is CORRECT but reason is INCORRECT
D. If assertion is INCORRECT but reason is CORRECT

Answer

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

**Assertion:** Lead, tin, and bismuth are purified by the liquation method.
**Reason:** Lead, tin, and bismuth have low melting points compared to impurities.

### Step-by-Step Solution:

1. **Understanding the Assertion:**
- The assertion states that lead, tin, and bismuth are purified using the liquation method.
- The liquation method is a metallurgical process used to separate metals from their ores or impurities based on differences in melting points.

2. **Understanding the Reason:**
- The reason given is that lead, tin, and bismuth have lower melting points compared to their impurities.
- This is a crucial point because the liquation method relies on the fact that the desired metal (lead, tin, bismuth) will melt and flow away while the impurities remain solid due to their higher melting points.

3. **Analyzing the Process:**
- In the liquation process, a mixture containing the metal and its impurities is heated.
- Since lead, tin, and bismuth have lower melting points, they will melt first.
- The molten metal can then flow away from the solid impurities, which do not melt at the same temperature.

4. **Conclusion:**
- Both the assertion and the reason are correct.
- The reason provided accurately explains why the assertion is true: the lower melting points of lead, tin, and bismuth compared to their impurities allow for their purification through liquation.

5. **Final Answer:**
- Both the assertion and reason are correct, and the reason is the correct explanation of the assertion.