How many alkenes, alkynes and alkadienes can be hydrogenated to form Isopentane (Including all structural isomers)

Answer

To determine how many alkenes, alkynes, and alkadienes can be hydrogenated to form isopentane, we will analyze the structures of these compounds step by step.

### Step 1: Understand the Structure of Isopentane
Isopentane, also known as 2-methylbutane, has the following structure:
- It consists of a five-carbon chain with a methyl group (−CH₃) attached to the second carbon.
- The molecular formula for isopentane is C₅H₁₂.

### Step 2: Identify Possible Alkenes
We need to identify alkenes that can be hydrogenated to yield isopentane. The alkenes must have the same number of carbon atoms (5) and should have at least one double bond.

1. **2-Methylbut-2-ene**:
- Structure: CH₃C(CH₃)=C(CH₃)CH₂
2. **2-Methylbut-1-ene**:
- Structure: CH₂=CHC(CH₃)CH₃
3. **3-Methylbut-1-ene**:
- Structure: CH₂=C(CH₃)CH₂CH₃

Total alkenes = 3

### Step 3: Identify Possible Alkynes
Next, we will identify alkynes that can be hydrogenated to yield isopentane. Alkynes must also have 5 carbon atoms and at least one triple bond.

1. **1-Pentyne**:
- Structure: CH≡C-CH₂-CH₂-CH₃

Total alkynes = 1

### Step 4: Identify Possible Alkadienes
Now, we will look for alkadienes that can be hydrogenated to yield isopentane. Alkadienes must have 5 carbon atoms and at least two double bonds.

1. **1,3-Pentadiene**:
- Structure: CH₂=CH-CH=CH-CH₃
2. **1,4-Pentadiene**:
- Structure: CH₂=CH-CH₂-CH=CH₂

Total alkadienes = 2

### Step 5: Calculate the Total Number of Compounds
Now, we can sum up the total number of alkenes, alkynes, and alkadienes:
- Alkenes: 3
- Alkynes: 1
- Alkadienes: 2

**Total = 3 (alkenes) + 1 (alkyne) + 2 (alkadienes) = 6**

### Final Answer
The total number of alkenes, alkynes, and alkadienes that can be hydrogenated to form isopentane (including all structural isomers) is **6**.

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