AIIMS2019Chemistry-Organic Chemistry

AIIMS 2019 Chemistry IUPAC Nomenclature MCQ Question

Type: MCQ-conceptual-Medium-Class 11

Assertion : The name of the hydrocarbon (CH3)2CHCH2CH2CH(CH3)CH2CH3(\text{CH}_3)_2\text{CHCH}_2\text{CH}_2\text{CH}(\text{CH}_3)\text{CH}_2\text{CH}_3 is 2,5-dimethylheptane and not 3,6-dimethylheptane.

Reason : Numbering should be done in such a way that the sum of the locants on the parent chain is the biggest possible number.

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

If both assertion and reason are true but reason is not the correct explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Correct Answer

Option C

Detailed Explanation

In organic chemistry, when numbering the carbon chain of a branched alkane, the numbering begins from the terminal carbon that is closest to a substituent or branching point. This ensures that the substituents receive the lowest possible numbers, which is a fundamental rule in IUPAC nomenclature. Option C correctly identifies this principle, while options A and B do not provide relevant information or context, making them incorrect. Understanding this concept is crucial for accurately naming organic compounds and recognizing their structure.

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