Which is the decreasing order of stability
(i) `CH_(3)-overset(+)(CH)-CH_(3)`
(ii) `CH_(3)-overset(+)(CH)-O-CH_(3)`
(iii) `CH_(3)-overset(+)(CH)-CO-CH_(3)`

Options

A. `(i) lt (ii) lt (iii)`
B. `(ii) lt (i) lt (iii)`
C. `(iii) gt (ii) gt (i)`
D. `(ii) gt (iii) gt (i)`

Answer

B

Explanation

`CH_(3) - overset(+)( C) H- OCH_(3)` is resonance stabilised as
Due to such resonance stability, the formed carbocation is most stable among all the given carbocations.
`CH_(3) - overset(+) ( C) H- CH_(3)` is less stable than earlier but more stable than `CH_(3) - CH - overset(O)overset(||) (C ) - CH_(3)`
Hence the correct order is
`(ii) gt (i) gt (iii)`.