Alkene Questions - Practice Questions of Alkene with Answer ... - Free Printable

The image you've uploaded shows five different alkene structures with their corresponding IUPAC names. The task appears to be related to naming alkenes or understanding the structure and nomenclature of alkenes, which are hydrocarbons containing at least one carbon-carbon double bond (C=C).

Let’s go through each structure, verify its name, and explain the reasoning behind the IUPAC naming.

---

1. CH₂=CH–CH₂–CH₂–CH₃

- Name: *Pent-1-ene*
- Explanation:
- The longest carbon chain has 5 carbons → "pent".
- There is a double bond between C1 and C2 → "1-ene".
- Numbering starts from the end closest to the double bond.
- So, it's pent-1-ene.

✔ Correct.

---

2. CH₃–CH=CH–CH₂–CH₃

- Name: *Pent-2-ene*
- Explanation:
- Longest chain: 5 carbons → "pent".
- Double bond between C2 and C3 → "2-ene".
- Numbering can start from either end (symmetrical in terms of position), so it's unambiguous.
- Hence, pent-2-ene is correct.

✔ Correct.

---

3. CH₃–C(CH₃)=CH–CH₃

- Structure:
```
CH₃
|
CH₃–C=CH–CH₃
```
- Name: *2-Methylbut-2-ene*
- Explanation:
- Longest chain with double bond: 4 carbons → "but".
- Double bond between C2 and C3 → "2-ene".
- A methyl group (-CH₃) is attached to C2.
- So, the compound is 2-methylbut-2-ene.
- Note: The carbon at C2 is part of the double bond and has two methyl groups — this is a trisubstituted alkene.

✔ Correct.

---

4. CH₃–CH(CH₃)–CH=CH₂

- Structure:
```
CH₃
|
CH₃–CH–CH=CH₂
```
- Name: *3-Methylbut-1-ene*
- Explanation:
- Longest chain including the double bond: 4 carbons → "but".
- Double bond starts at C1 → "1-ene".
- Methyl group is on C3 (counting from the double bond end).
- So, 3-methylbut-1-ene.
- Important: We number the chain so that the double bond gets the lowest possible numbers.

✔ Correct.

---

5. CH₂=C(CH₃)–CH₂–CH₃

- Structure:
```
CH₃
|
CH₂=C–CH₂–CH₃
```
- Name: *2-Methylbut-1-ene*
- Explanation:
- Longest chain with double bond: 4 carbons → "but".
- Double bond between C1 and C2 → "1-ene".
- A methyl group is attached to C2.
- So, 2-methylbut-1-ene.
- This is a disubstituted alkene at C2 (with two alkyl groups: methyl and ethyl).

✔ Correct.

---

Summary:

All five structures are correctly named according to IUPAC rules for alkenes:

| Structure | Name |
|---------|------|
| CH₂=CH–CH₂–CH₂–CH₃ | Pent-1-ene |
| CH₃–CH=CH–CH₂–CH₃ | Pent-2-ene |
| CH₃–C(CH₃)=CH–CH₃ | 2-Methylbut-2-ene |
| CH₃–CH(CH₃)–CH=CH₂ | 3-Methylbut-1-ene |
| CH₂=C(CH₃)–CH₂–CH₃ | 2-Methylbut-1-ene |

---

Key IUPAC Rules Applied:

1. Identify the longest continuous carbon chain that includes the double bond.
2. Number the chain to give the double bond the lowest possible number.
3. Name substituents (like methyl) with their positions.
4. Use "ene" suffix to indicate presence of a double bond.
5. Position of double bond is indicated by the lower-numbered carbon involved.

---

Final Answer:

✔ All given names are correct based on IUPAC nomenclature rules.

If your task was to verify the names, then the answer is: Yes, all names are correctly assigned.

If the task was something else (e.g., identify structural isomers, predict reactions, etc.), please clarify — but based on the image, naming verification seems most likely.