Which of the following compounds will not exist as resonance hybrid? Give reason for your answer.
(a) `CH_(3)OH` (b) `R- CONH_(2)` (c ) `CH_(3)CH= CHCH_(2)NH_(2)`

Explanation

(a) `CH_(3)OH` does not contain `pi`-electron and hence it cannot be regarded as a resonance hybrid.
(b) The complete structure of `R- CONH_(2)` is as under

In this 1-(lone pair), 2- (`pi`-electron), 3-single bond and 4 nonbonding p electron on N and alternate `pi` bond system is present so following rsonance structure can be expressed

`therefore` (b) `RCONH_(2)` has possible resonance structure.
(c ) In this alteranate `pi//p` electrons are not there and C=C has more than one singma bond. So in C resonance is not possible.