A:1,3-butadiene is the monomer for natural rubber.
R: Natural rubber is formed through anionic addition polymerisation.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark 1.
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark 2.
C. If Assertion is true statement but Reason is false, then mark 3.
D. If both Assertion and Reason are false statements the mark 4.

Answer

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

### Step 1: Analyze the Assertion
The assertion states that "1,3-butadiene is the monomer for natural rubber."

- **Explanation**: Natural rubber is primarily derived from the polymerization of isoprene (2-methyl-1,3-butadiene), not 1,3-butadiene. Therefore, this assertion is incorrect.

### Step 2: Analyze the Reason
The reason states that "Natural rubber is formed through anionic addition polymerization."

- **Explanation**: The polymerization of isoprene occurs through cationic addition polymerization, not anionic. The presence of the methyl group in isoprene makes it more likely to undergo cationic polymerization due to the electron-donating nature of the methyl group. Therefore, this reason is also incorrect.

### Step 3: Conclusion
Since both the assertion and the reason are incorrect, the correct answer to the question is that both statements are false.

### Final Answer
Both the assertion and the reason are false statements.

---