Which of the following are correct ?

Options

A. `CH_(3)-O-CH_(2)^(o+)"is more stable than" CH_(3)-CH_(2)^(o+)`
B. `(CH_(3))_(2)CH^(o+)"is less stable than"CH_(3)-CH_(2)-CH_(2)^(o+)`
C. `C_(2)=CH-CH_(2)^(o+)"is more stable than"CH_(3)-CH_(2)-CH_(2)^(o+)`
D. `CH_(2)=CH^(o+)"is more stable than" CH_(3)-CH_(2)^(o+)`

Answer

A, C

Explanation

(i) + I-effect increases the stability of carbocation + I-effect of i.e., `CH_(3)-Ogt-CH_(3)`. Thus, `CH_(3)-O-overset(+)(CH_(2))` is more stable than `CH_(3)-overset(+)(CH_(2))`.
(ii) `(CH_(3))_(2)CH^(+)` is more stable than `CH_(3)-C_(2)-overset(+)(CH_(2))` because former has stabilised by + I-effect of two `-CH_(3)` groups.
(iii) `CH_(2)=CH-overset(+)(CH_(2))harroverset(+)(CH_(2)-CH=CH_(2)` is stabilised by strong resonance effect while `CH_(3)-CH_(2)-CH_(2)` is stabilised by weak +I-effect of the `CH_(3)CH_(2)` group.
(iv) In `CH_(2)=overset(+)(CH), +ve` charge is present , on the moer electrongatiue, sp-hybridised carbon while in `CH_(3)-CH_(2), +ve` charge is present on the less electronegative `sp^(2)`-hybridised carbon therefore, `CH_(2)-overset(+)(CH)` is less stable than `CH_(3)-overset(+)(CH_(2)`.
`CH_(2)=underset(sp^(2))(CH)-CH^(+)`
`CH_(3)-underset(sp^(3))(CH_(2))-overset(+)(CH_(2))`