Q6 · CSIR NET Chemistry, June 2015
Paper: CSIR NET June 2015 · Subject: Organic Chemistry · Chapter: General Organic Chemistry · Topic: General Organic Chemistry – General · Marks: 2 · Difficulty: Hard
The correct order of heat of hydrogenation for the following compounds is 
(I) (II) (III) (IV)
(I) (II) (III) (IV)(a)I $>$ II $>$ III $>$ IV
(b)I $>$ III $>$ II $>$ IV
(c)IV $>$ I $>$ III $>$ II
(d)IV $>$ II $>$ I $>$ III
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
The more substituted and the trans alkenes are more stable and so release less heat on hydrogenation. 1-Pentene > cis-2-pentene > trans-2-pentene > 2-methyl-2-butene: I > III > II > IV (b).
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