The nitration of a compound is due to the

Which of the following is an electrophilic reagent?

Giving justification,categorise the following molecules/ions as nucleophile or electrophile: $HS^{-}, BF_{3}, C_{2}H_{5}O^{-}, (CH_{3})_{3}N:, \overset{+}{Cl}, CH_{3}-\overset{+}{C}=O, H_{2}N:^{-}, \overset{+}{N}O_{2}$

Identify the electrophilic centers in the following: $CH_3-CHO$,$CH_3-CN$,and $CH_3-I$.

What is the decreasing order of nucleophilicity for $R_3C^{-}, R_2N^{-}, RO^{-},$ and $F^{-}$?

Which of the following is not an electrophile?