Write IUPAC names of the products obtained by the ozonolysis of the following compounds:
(i) Pent-2-ene (ii) 3,4-Dimethyl-hept-3-ene
(iii) 2-Ethylbut-1-ene (iv) 1-Phenylbut-1-ene

Explanation

To solve the problem of determining the IUPAC names of the products obtained by the ozonolysis of the given compounds, we will go through each compound step by step.

### Step 1: Ozonolysis of Pent-2-ene
1. **Identify the structure**: Pent-2-ene has the structure CH3-CH=CH-CH2-CH3.
2. **Ozonolysis reaction**: The double bond between the second and third carbon atoms will break, and ozone will add to form an ozonide intermediate.
3. **Reduction**: The ozonide is then reduced using zinc and water, leading to the formation of two carbonyl compounds.
4. **Products**: The products are:
- Ethanal (acetaldehyde) from the terminal carbon.
- Propan-2-one (acetone) from the central carbon.
5. **IUPAC Names**: The final products are Ethanal and Propan-2-one.

### Step 2: Ozonolysis of 3,4-Dimethylhept-3-ene
1. **Identify the structure**: 3,4-Dimethylhept-3-ene has the structure CH3-CH(CH3)-C(CH3)=CH-CH2-CH3.
2. **Ozonolysis reaction**: The double bond at the third position will break, forming an ozonide.
3. **Reduction**: The ozonide is reduced to yield two carbonyl compounds.
4. **Products**: The products are:
- Butan-2-one from the left side of the double bond.
- Pentan-2-one from the right side of the double bond.
5. **IUPAC Names**: The final products are Butan-2-one and Pentan-2-one.

### Step 3: Ozonolysis of 2-Ethylbut-1-ene
1. **Identify the structure**: 2-Ethylbut-1-ene has the structure CH3-CH=CH-CH2-CH3 with an ethyl group on the second carbon.
2. **Ozonolysis reaction**: The double bond will break, forming an ozonide.
3. **Reduction**: The ozonide is reduced to yield two carbonyl compounds.
4. **Products**: The products are:
- Methanal (formaldehyde) from the terminal carbon.
- Pentan-3-one from the central carbon.
5. **IUPAC Names**: The final products are Methanal and Pentan-3-one.

### Step 4: Ozonolysis of 1-Phenylbut-1-ene
1. **Identify the structure**: 1-Phenylbut-1-ene has the structure C6H5-CH=CH-CH2-CH3.
2. **Ozonolysis reaction**: The double bond will break, forming an ozonide.
3. **Reduction**: The ozonide is reduced to yield two carbonyl compounds.
4. **Products**: The products are:
- Benzaldehyde from the phenyl side.
- Propan-2-one from the butyl side.
5. **IUPAC Names**: The final products are Benzaldehyde and Propan-2-one.

### Summary of IUPAC Names of Products:
- (i) Pent-2-ene → Ethanal and Propan-2-one
- (ii) 3,4-Dimethylhept-3-ene → Butan-2-one and Pentan-2-one
- (iii) 2-Ethylbut-1-ene → Methanal and Pentan-3-one
- (iv) 1-Phenylbut-1-ene → Benzaldehyde and Propan-2-one