Electronic Effects

Most stable and least stable species respectively among the following are

The correct stability order of the following resonance structure is

Number of hyperconjugate hydrogen of propene is

In which of the following molecules positive charge is not delocalized because of resonance?

Resonance is not possible in

Which of the following group will have strongest electron donating mesomeric effect?

In the given anion, $-\mathrm{ve}$ charge is delocalized on 

At conjugated position $-{\mathrm{NO}}_2$ imparts

In which of the following all electronic effects namely inductive, mesomeric and hyperconjugative effects are present?

Arrange following three given aromatic compounds in increasing order of resonance energy per ring.

Which of the following is most stabilised by hyperconjugation?

In which of the following alkene hyperconjugation does not take place?

Which of the following pairs are resonance structures?

I. ${\mathrm{CH}}_3\mathrm{CH}={\mathrm{CH}}_2$  and  

II. 

III. 

 IV. ${\mathrm{CH}}_3-\mathrm{O}-{\mathrm{CH}}_3$ and ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$

The most stable resonating structure of methoxyethene is

Among the following three canonical structures what would be their relative contribution in hybrid?

I. ${\mathrm{CH}}_2=\mathrm{CH}-\underset{+}{\mathrm{C}}-\underset{-}{\mathrm{C}}\mathrm{H}-\mathrm{CH}={\mathrm{CH}}_2$

II. ${\mathrm{CH}}_2=\mathrm{CH}-\stackrel{+}{\mathrm{C}}\mathrm{H}-\mathrm{CH}=\mathrm{CH}-\stackrel{-}{\mathrm{C}}{\mathrm{H}}_2$

III. $\stackrel{+}{\mathrm{C}}{\mathrm{H}}_2-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}-\stackrel{-}{\mathrm{C}}{\mathrm{H}}_2$

Given set of resonating structures and their stability is provided in bracket. Select which one is incorrectly matched.

In which of the following species lone pair ${\mathrm{e}}^{-}$ at Nitrogen atom is not involved in delocalization?

Choose the correcct statement.

The inductive effects of the groups 

are respectively

The mesomeric effects of the groups

are respectively.