Question

The structure of isoprene is:

• A. ${\mathrm{CH}}_2=\mathrm{C}\left({\mathrm{C}}_2{\mathrm{H}}_5\right)-\mathrm{CH}={\mathrm{CH}}_2$
• B. ${\mathrm{CH}}_2=\mathrm{C}\left({\mathrm{OCOCH}}_3\right)-\mathrm{CH}={\mathrm{CH}}_2$
• C. ${\mathrm{CH}}_2=\mathrm{C}\left({\mathrm{CH}}_3\right)-\mathrm{CH}={\mathrm{CH}}_2$
• D. ${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{C}=\mathrm{CH}$

Answer 1

The correct option is C

${\mathrm{CH}}_2=\mathrm{C}\left({\mathrm{CH}}_3\right)-\mathrm{CH}={\mathrm{CH}}_2$

The IUPAC name of Isoprene is 2-Methyl-1,3-butadiene. Structure of Isoprene can be identified as:

1: Identification of Root Word

The name “Buta” determines that the chain is having 4 carbon atoms.

2. Determination of positions of groups:

There is one substituent (methyl group) present at the second position and the suffix “diene” confirms the presence of two double bonds after the first and third carbon of the chain.

3. Determination of structure:

Thus, the structure of the isoprene will be:

${\mathrm{CH}}_2=\mathrm{C}\left({\mathrm{CH}}_3\right)-\mathrm{CH}={\mathrm{CH}}_2$

Final Answer:

Hence, option (C) is correct.