Which of the following alkenes is expected to be more reactive towards electrophilic addition reactions ?

Options

A. `(CH_(3))_(2)C = CH_(2)`
B. `(CH_(3))_(2) C = CH_"CH_(3)`
C. `CH_(2) = CH_(2)`
D. `(CH_(3))_(2) C = C (CH_(3))_(2)`

Answer

D

Explanation

`(CH_(3))_(2)C = C(CH_(3))_(2) overset(HX)rarr underset((3^(@)-"carbocation"))(CH_(3) - underset(oplus)overset(CH_(3))overset(|)(C) - underset(H)underset(|)overset(CH_(3))overset(|)(C)-CH_(3)) overset(X^(-))rarr CH_(3) - underset(X)underset(|)overset(CH_(3))overset(|)(C) - underset(H)underset(|)overset(CH_(3))overset(|)(C) - CH_(3)`
This reaction proceeds through the formation of stable `(3^(@))` carbocation ion while others proceed through the formation of relatively less stable `(1^(@) or 2^(@))` carbocations.