What is incorrect regarding natural rubber?
1. It is cis polyisoprene
2. It is amorphous in nature
3. It has syndiotactic stereochemisty
4. Molecules of rubber have coiled conformation

Options

A. 1,2
B. 2,4
C. 1,2,3
D. 1,2,4

Answer

To determine which statement regarding natural rubber is incorrect, let's analyze each option step by step.

### Step 1: Analyze Option 1
**Statement**: It is cis polyisoprene.
**Analysis**: Natural rubber is primarily composed of polyisoprene, which is indeed in the cis configuration. Therefore, this statement is **correct**.

### Step 2: Analyze Option 2
**Statement**: It is amorphous in nature.
**Analysis**: Natural rubber does exhibit amorphous characteristics in its unstrained state. However, when stretched, it can exhibit crystalline properties. Thus, this statement is **correct** as it can be considered amorphous in its natural state.

### Step 3: Analyze Option 3
**Statement**: It has syndiotactic stereochemistry.
**Analysis**: Natural rubber has isotactic stereochemistry, not syndiotactic. Syndiotactic refers to a specific arrangement of the polymer chains that is not present in natural rubber. Therefore, this statement is **incorrect**.

### Step 4: Analyze Option 4
**Statement**: Molecules of rubber have coiled conformation.
**Analysis**: The long polymer chains in rubber do tend to coil due to their flexible nature. This statement is **correct**.

### Conclusion
Based on the analysis:
- Option 1: Correct
- Option 2: Correct
- Option 3: Incorrect
- Option 4: Correct

Thus, the incorrect statement regarding natural rubber is **Option 3**, which states that it has syndiotactic stereochemistry.