Which does not contain an asymmetric carbon atom?
A) CH₃CH(CH₃)CH₂CH₃
B) CH₃CH₂CH(CH₃)CH₂CH₃
C) CH₃CH(OH)CH(OH)CH₂OH
D) CH₃CH2CHClCH₃ - AQA - A-Level Chemistry - Question 26 - 2020 - Paper 3
Question 26
Which does not contain an asymmetric carbon atom?
A) CH₃CH(CH₃)CH₂CH₃
B) CH₃CH₂CH(CH₃)CH₂CH₃
C) CH₃CH(OH)CH(OH)CH₂OH
D) CH₃CH2CHClCH₃
Worked Solution & Example Answer:Which does not contain an asymmetric carbon atom?
A) CH₃CH(CH₃)CH₂CH₃
B) CH₃CH₂CH(CH₃)CH₂CH₃
C) CH₃CH(OH)CH(OH)CH₂OH
D) CH₃CH2CHClCH₃ - AQA - A-Level Chemistry - Question 26 - 2020 - Paper 3
Step 1
A) CH₃CH(CH₃)CH₂CH₃
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Answer
This structure has a carbon atom with four different groups attached: methyl (CH₃), ethyl (CH₂), another methyl (CH₃), and a hydrogen (H). Therefore, it is asymmetric.
Step 2
B) CH₃CH₂CH(CH₃)CH₂CH₃
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Answer
In this structure, the carbon atom already has three identical branches (ethyl groups around the central carbon), making it symmetric. Hence, it does not contain an asymmetric carbon.
Step 3
C) CH₃CH(OH)CH(OH)CH₂OH
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Answer
This structure features a carbon atom with four distinct groups (two hydroxyl groups and two other carbon substituents), presenting an asymmetric carbon.
Step 4
D) CH₃CH₂CHClCH₃
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Answer
In this case, the carbon connected to chlorine has three different substituents (methyl, ethyl, and chlorine), making it asymmetric.
