Hydrocarbons - Result Question 47
30. Which one of the following has the smallest heat of hydrogenation per mole?
(1993,1 M)
(a) $1$-butene
(b) trans-$2$-butene
(c) cis-$2$-butene
(d) $1, 3$-butadiene
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Answer:
Correct Answer: 30. (b)
Solution:
- Among alkenes-heat of hydrogenation depends on :
(a) The number of double bonds-greater, greater the amount of heat evolved in hydrogenation.
Hence, $1, 3$-butadiene has highest heat of hydrogenation among these.
(b) Relative stability of alkenes-greater the stability, smaller the heat evolved in hydrogenation. trans-$2$-butene is most stable among three given butenes, has least heat of hydrogenation.
BETA
