Natural rubber is a polymer of

Options

A. butadiene
B. ethylene
C. isoprene
D. neoprene

Answer

To solve the question "Natural rubber is a polymer of," we need to identify the monomer unit that polymerizes to form natural rubber. Here’s a step-by-step solution:

### Step 1: Identify the Monomer
Natural rubber is primarily made from the polymerization of a specific monomer. The monomer for natural rubber is **isoprene**.

### Step 2: Understand the Structure of Isoprene
Isoprene has the chemical structure:
\[ \text{CH}_2=C(\text{CH}_3)-CH=CH_2 \]
This structure indicates that isoprene contains two double bonds.

### Step 3: Polymerization Process
When isoprene undergoes polymerization, it forms a long chain polymer. The polymerization process can be represented as:
\[ n \, \text{(isoprene)} \rightarrow \text{cis-polyisoprene} \]
where \( n \) is the number of isoprene units that combine to form the polymer.

### Step 4: Identify the Type of Polymer
The polymer formed from isoprene is known as **cis-polyisoprene**, which is the chemical name for natural rubber.

### Step 5: Distinguish from Other Forms
While cis-polyisoprene is natural rubber, there is also a trans form known as **gutta-percha**, which is another polymer of isoprene but has different properties.

### Conclusion
Thus, the answer to the question "Natural rubber is a polymer of" is **isoprene**.

### Final Answer
Natural rubber is a polymer of **isoprene**.

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