The hydrogenation of some compounds to cyclohexane generates the following amount of heat:(kcal/mol)

Cyclohexene                 -28    1,3-cyclohexadiene         -54

1,4-cyclohexadiene       -56     Benzene                         -49

Based on these data, the best estimate of the resonance energy of benzene 

The most acidic proton and the strongest nucleophilic nitrogen in the following compound

respectively, are

Given below are two statements :

Statement I : Hyperconjugation is a permanent effect.

Statement II : Hyperconjugation in ethyl cation $\left({\mathrm{CH}}_3-\stackrel{+}{\mathrm{C}}{\mathrm{H}}_2\right)$ involves the overlapping of ${\mathrm{C}}_{{\mathrm{sp}}^2}-{\mathrm{H}}_{1\mathrm{s}}$ bond with empty $2\mathrm{p}$ orbital of other carbon.

Choose the correct option:

The chlorine atom of the following compound

that reacts most readily with ${\mathrm{AgNO}}_3$ to give a precipitate is

Among the given species the Resonance stabilised carbocations are:

The correct order of decreasing of reactivity towards ${\mathrm{H}}_3{\mathrm{PO}}_4$ of the following compounds is

The following effect is known as___