Resonance Effects

Which one of the following statements is true: 

The most stable canonical structure of this molecule is:

Which of these cyclopropene systems is aromatic ?

In which of the following molecules / ions resonance structures are equivalent:

Which of the following has longest C-O bond:

There are three canonical structures of naphthalene. Examine them and find the correct statement among the following:

In which of the following pairs, is the first species is more stable than second?

In which of the following molecules π-electron density in ring is maximum ?

Which of the following compounds has maximum electron density in ring ?

Which of the following compounds has maximum electron density in ring ?

In phenol, π - electron - density is maximum on

The least stable canonical structure among these is

The order of stability of these canonical forms is:

The most stable resonating structure of following compound is

$\left(\mathrm{I}\right){\mathrm{CH}}_3-\mathrm{O}-\mathrm{CH}=\mathrm{CH}-{\mathrm{CH}=\mathrm{CH}}_2$

$\left(\mathrm{II}\right){\mathrm{CH}}_3-\mathrm{O}-\stackrel{\oplus }{\mathrm{C}}\mathrm{H}-\mathrm{CH}={\mathrm{CH}-\stackrel{\ominus }{\mathrm{C}}\mathrm{H}}_2$

$\left(\mathrm{III}\right){\mathrm{CH}}_3-\stackrel{\oplus }{\mathrm{O}}=\mathrm{CH}-\mathrm{CH}={\mathrm{CH}-\stackrel{\ominus }{\mathrm{C}}\mathrm{H}}_2$

Among these three canonical structures (through more are possible) what would be their relative contribution in the hybrid?

$\begin{array}{cc}\left(\text{I}\right)& {\text{CH}}_2=\underset{\updownarrow }{\text{C}}\text{H}-\text{CH}=\text{CH}-\text{O}{\text{CH}}_3\\ \left(\text{I}\text{I}\right)& \stackrel{\ominus }{\text{C}}{\text{H}}_2-\underset{\updownarrow }{\text{C}}\text{H}=\text{CH}-\text{CH}=\stackrel{\oplus }{\text{O}}{\text{CH}}_3\\ \left(\text{III}\right)& {\text{CH}}_2=\underset{\updownarrow }{\text{C}}\text{H}-\stackrel{\ominus }{\text{C}}\text{H}-\stackrel{\oplus }{\text{C}}\text{H}-\text{O}{\text{CH}}_3\\ \left(\text{IV}\right)& {\text{CH}}_2=\text{CH}-\stackrel{\oplus }{\text{C}}\text{H}-\stackrel{\ominus }{\text{C}}\text{H}-\text{O}{\text{CH}}_3\end{array}$

Among these canonical structures which one is least stable ?

In which of the following molecules - ${\text{NO}}_2$ group is not coplanar with phenyl ring?

Which of the following compound do not give the protonation reaction readily?

Among the following, the least stable resonance structure is