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In 1869 Ladenburg suggested a structure for benzene, C₆H₆, in which one hydrogen atom is attached to each carbon atom - CIE - A-Level Chemistry - Question 28 - 2015 - Paper 1
Question 28
In 1869 Ladenburg suggested a structure for benzene, C₆H₆, in which one hydrogen atom is attached to each carbon atom. A compound C₆H₄Cl₂ could be formed with the s... show full transcript
Worked Solution & Example Answer:In 1869 Ladenburg suggested a structure for benzene, C₆H₆, in which one hydrogen atom is attached to each carbon atom - CIE - A-Level Chemistry - Question 28 - 2015 - Paper 1
Step 1
How many structural isomers would this compound have?
Answer
To determine the number of structural isomers for the compound C₆H₄Cl₂ (with the same skeleton as the Ladenburg structure), we need to consider the positions where the chlorine atoms can be substituted on the benzene ring.
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Identify Positions: In the benzene structure provided, there are 6 carbon atoms arranged in a ring, each with a hydrogen that can be replaced by chlorine.
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Substitution Patterns: The two chlorine atoms can either be:
- On the same carbon (1,1-dichloro)
- Adjacent to each other (1,2-dichloro)
- Separated by one carbon (1,3-dichloro)
- Opposite each other (1,4-dichloro)
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Count Isomers: For C₆H₄Cl₂, the structural isomers are:
- 1,2-dichlorobenzene (ortho)
- 1,3-dichlorobenzene (meta)
- 1,4-dichlorobenzene (para)
- 1,1-dichlorobenzene (cumulative)
In total, there are 4 structural isomers for C₆H₄Cl₂.