Which of the following is most stable ?

Options

A. 1-butene
B. 1-pentene
C. 2-butene
D. 2-pentene

Answer

D

Explanation

`underset("(2-butene)")(CH_(3)-CH=CH-CH_(3))" "underset("(1-butene)")(CH_(3)-CH_(2)-CH=CH_(2))`
`underset("(1-pentene)")(CH_(3)-CH_(2)-CH_(2)-CH=CH_(2))" " underset("(2-pentene)")(CH_(3)-CH_(2)-CH=CH-CH_(3))`
According to Saytzeff rule , stability of alkenes depends upon the substitution on C=C bond. More of substitution by alkyl group , the more stable is the alkene.