Which alkene on ozonolysis gives `CH_(3)CH_(2)CHO` and `CH_(3)underset(O)underset(||)(C )CH_(3)` ?

Options

A.
B. `CH_(3)CH_(2)CH=CHCH_(2)CH_(3)`
C. `CH_(3)CH_(2)CH=CHCH_(3)`
D. `CH_(3)-underset(CH_(3))underset(|)C=CHCH_(3)`

Answer

To determine which alkene on ozonolysis gives the products CH₃CH₂CHO (an aldehyde) and CH₃C(=O)CH₃ (a ketone), we can follow these steps:

### Step 1: Identify the Products
We need to recognize the products we are looking for:
- CH₃CH₂CHO is propanal (an aldehyde).
- CH₃C(=O)CH₃ is acetone (a ketone).

### Step 2: Write the General Reaction for Ozonolysis
In ozonolysis, alkenes react with ozone (O₃) to form ozonides, which can then be hydrolyzed to yield carbonyl compounds (aldehydes and ketones). The general reaction can be represented as:
\[ \text{Alkene} + O_3 \rightarrow \text{Ozonide} \rightarrow \text{Aldehyde} + \text{Ketone} \]

### Step 3: Consider Possible Alkenes
We need to find an alkene that can yield both propanal and acetone upon ozonolysis. Let's consider the structure of the alkene:
- The alkene should have a double bond that can lead to the formation of one aldehyde and one ketone.

### Step 4: Analyze the Given Products
From the products:
1. **Propanal (CH₃CH₂CHO)** suggests that one of the fragments must have a terminal carbon (the carbonyl carbon of the aldehyde).
2. **Acetone (CH₃C(=O)CH₃)** suggests that the other fragment must have two methyl groups attached to the carbonyl carbon.

### Step 5: Construct the Alkene
To produce these products, we can deduce that the alkene must be:
\[ \text{CH}_3\text{CH}_2\text{C}=\text{C}\text{CH}_3 \]
This is 3-pentene.

### Step 6: Perform Ozonolysis on the Alkene
When ozonolysis is performed on 3-pentene:
1. The double bond between the second and third carbon is cleaved.
2. This results in the formation of:
- CH₃CH₂CHO (propanal)
- CH₃C(=O)CH₃ (acetone)

### Conclusion
Thus, the alkene that gives CH₃CH₂CHO and CH₃C(=O)CH₃ upon ozonolysis is **3-pentene**.