Question

Draw the structural isomers of the alkene \(\mathrm{C}_{4} \mathrm{H}_{8}\).

Short answer

Answer: The structural isomers of the alkene C4H8 are 1-butene (but-1-ene), 2-butene (but-2-ene), and 2-methylpropene.

Step-by-step solution

1. Identify the molecular formula of the given alkene

The molecular formula of the given alkene is C4H8, which means it contains 4 carbon atoms and 8 hydrogen atoms.

2. Draw the backbone structure of the carbon chain

To form different structural isomers, we can arrange the 4 carbon atoms in a straight chain or in a branched chain. In the straight chain, there are 4 carbons in a row, while in the branched chain, three carbons are in a row, and the fourth carbon is attached to the second carbon. We can denote the carbon atoms as C1, C2, C3, and C4, respectively.

3. Position of the double bond

Now, we must position the double bond between the carbon atoms in different ways. When the double bond is between C1 and C2, the isomer is called 1-butene or but-1-ene, and when the double bond is between C2 and C3, the isomer is called 2-butene or but-2-ene.

4. Stereochemistry for the branched isomer

When the double bond is between C1 and the branched carbon (C2'), we have a new isomer, which is called 2-methylpropene.

5. Draw the structural formulas

We have identified the three possible structural isomers of C4H8, which can be represented by the following structural formulas: 1. 1-Butene or but-1-ene: H2C=CH-CH2-CH3 2. 2-Butene or but-2-ene: CH3-CH=CH-CH3 3. 2-Methylpropene: CH3C(CH3)=CH2 These are the structural isomers of the alkene C4H8.