AIIMS2018Chemistry-Organic Chemistry

AIIMS 2018 Chemistry Isomerism MCQ Question

Type: MCQ-conceptual-Medium-Class 11

Assertion : All CCC\text{C}-\text{C}-\text{C} bond angles in Isobutene, CH3C(CH3)=CH2\text{CH}_3-\text{C}(\text{CH}_3)=\text{CH}_2, are different.

Reason : CH3\text{CH}_3 (Methyl group) show steric crowding

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 A

Detailed Explanation

In isobutene (C₄H₈), the carbon atoms are arranged in a branched structure, resulting in bond angles of approximately 120° around the sp² hybridized carbon atoms due to trigonal planar geometry. This assertion is true, and the reason is that the presence of a double bond between one of the carbon atoms leads to this specific hybridization and bond angle, making it the correct explanation.

Option B is incorrect because while both statements are true, the reason directly explains the assertion. Options C and D are incorrect as they misrepresent the truth of the assertion and the reason, which are both valid in this context.

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