The ratio of $\sigma$ and $\pi$ bonds in benzene is:

Which of the following undergoes sulphonation at the fastest rate?

During the mixed acid nitration of benzene,concentrated $HNO_3$ behaves like:

The reaction$(s)$ leading to the formation of $1,3,5-$trimethylbenzene is (are):
$(A)$ $3CH_3COCH_3 \xrightarrow{Conc. H_2SO_4, \Delta} 1,3,5-\text{trimethylbenzene}$
$(B)$ $3CH_3C \equiv CH \xrightarrow{\text{heated iron tube}, 873 K} 1,3,5-\text{trimethylbenzene}$
$(C)$ $1,3,5-\text{triacetylbenzene} \xrightarrow{1) Br_2, NaOH, 2) H_3O^+, 3) \text{sodalime}, \Delta} \text{benzene}$
$(D)$ $1,3,5-\text{triformylbenzene} \xrightarrow{Zn/Hg, HCl} 1,3,5-\text{trimethylbenzene}$

The correct order of reactivity of $(I)$ Aniline,$(II)$ Benzene,and $(III)$ Nitrobenzene towards electrophilic substitution reaction is .....

The product $(B)$ in the above reaction is: