An alkene on ozonolysis gives methanal as one of the product. Its structure is :

Options

A.
B.
C.
D.

Answer

To solve the question of identifying the structure of an alkene that produces methanal (formaldehyde) upon ozonolysis, we can follow these steps:

### Step 1: Understand Ozonolysis
Ozonolysis is a reaction where an alkene reacts with ozone (O₃) to form carbonyl compounds. The double bond in the alkene is broken, and oxygen atoms are added to the resulting fragments.

### Step 2: Identify the Product
The question states that one of the products of ozonolysis is methanal (formaldehyde), which has the structure:
\[ \text{H}_2C=O \]
This indicates that one of the fragments produced must be a carbonyl compound with one carbon atom.

### Step 3: Analyze Possible Alkene Structures
We need to find an alkene that, when ozonolyzed, yields methanal as one of the products. We will analyze the given options one by one.

#### Option 1: Cyclohexene
1. Structure: Cyclohexene (C₆H₁₀)
2. Ozonolysis Reaction:
- Break the double bond and add oxygen.
- Products: Acetaldehyde (ethanal) and another carbonyl compound.
- Result: No methanal produced.

**Hint:** Cyclohexene does not yield methanal upon ozonolysis.

#### Option 2: 1-Hexene
1. Structure: 1-Hexene (C₆H₁₂)
2. Ozonolysis Reaction:
- Break the double bond and add oxygen.
- Products: Butanal and methanal.
- Result: Methanal is produced.

**Hint:** 1-Hexene can produce methanal upon ozonolysis.

#### Option 3: 1-Pentene
1. Structure: 1-Pentene (C₅H₁₀)
2. Ozonolysis Reaction:
- Break the double bond and add oxygen.
- Products: Propan-2-one and methanal.
- Result: Methanal is produced.

**Hint:** 1-Pentene can also produce methanal upon ozonolysis.

#### Option 4: 2-Pentene
1. Structure: 2-Pentene (C₅H₁₀)
2. Ozonolysis Reaction:
- Break the double bond and add oxygen.
- Products: Butan-2-one and methanal.
- Result: Methanal is produced.

**Hint:** 2-Pentene can also produce methanal upon ozonolysis.

### Step 4: Conclusion
After analyzing the options, we find that both 1-Hexene and 1-Pentene can produce methanal upon ozonolysis. However, the simplest alkene that directly leads to methanal is 1-Hexene.

### Final Answer
The structure of the alkene that gives methanal as one of the products upon ozonolysis is **1-Hexene**.