Natural rubber is a polymer of

Options

A. a. 1,1-dimethylbutadiene
B. b. 2-methyl-1,3-butadiene
C. c. 2-chlorobuta-1,3-diene
D. d. 2-chlorobut-2-ene.

Explanation

To solve the question "Natural rubber is a polymer of," we need to identify the correct monomer from the given options. Here’s a step-by-step solution:

### Step 1: Understand the Structure of Natural Rubber
Natural rubber is a polymer, which means it is made up of repeating units called monomers. The structure of natural rubber is derived from the polymerization of a specific monomer.

### Step 2: Identify the Monomer
The monomer that polymerizes to form natural rubber is known as 2-methyl-1,3-butadiene. This compound has the following structure:
- It contains a double bond between the first and second carbon atoms and between the third and fourth carbon atoms.
- The methyl group (–CH3) is attached to the second carbon.

### Step 3: Analyze the Given Options
Now, let's analyze the options provided:
a. 1,1-dimethylbutadiene
b. 2-methyl-1,3-butadiene
c. 2-chlorobuta-1,3-diene
d. 2-chlorobut-2-ene

Among these options, we need to find which one corresponds to the structure of 2-methyl-1,3-butadiene.

### Step 4: Confirm the Correct Option
- Option (b) 2-methyl-1,3-butadiene matches the structure we identified as the monomer of natural rubber.
- The other options do not correspond to the structure of natural rubber.

### Conclusion
Therefore, the correct answer is:
**Natural rubber is a polymer of 2-methyl-1,3-butadiene.**

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