An electrophile $E^{\oplus}$ attacks the benzene ring to form an intermediate $\sigma$-complex. Which of the following $\sigma$-complexes has the lowest energy?

Among the given compounds,the correct order of enol content is:
$(I)$ Cyclopentanone
$(II)$ $4$-hydroxycyclopent-$2$-en-$1$-one derivative
$(III)$ $\gamma$-butyrolactone derivative

In the following reaction,compound $Q$ is obtained from compound $P$ via an ionic intermediate. What is the degree of unsaturation of $Q$?

The heterolytic decomposition of the carbon-chlorine bond forms:

Consider the above reaction,the major product $P$ formed is:

Match Column-$I$ and Column-$II$ with the correct relation:

Column-$I$	Column-$II$
$(i)$ Substitution reaction	$(p)$ $CH_2=CH_2 + Br_2 \to CH_2Br-CH_2Br$
$(ii)$ Addition reaction	$(q)$ $C_6H_6 + NO_2^+ \to C_6H_5NO_2 + H^+$
$(iii)$ Electrophilic addition reaction	$(r)$ $CH_3Cl + NaOH \to CH_3OH + NaCl$
$(iv)$ Electrophilic substitution reaction	$(s)$ $CH_3CH_2OH \xrightarrow[\Delta]{Al_2O_3} CH_2=CH_2$
$(v)$ Elimination reaction