Question

Electrophiles are electron seeking species. Which of the following groups contains only electrophiles?

• A. $B{F}_3,N{H}_3,H_{2}O$
• B. $AlC{l}_3,S{O}_3,N{O}_2^{+}$
• C. $N{O}_2^{+},C{H}_3^{+},C{H}_3-C^{+}=O$
• D. $\cdot$
  $C_2{H}_5^{-},C_2{H}_5,C_2{H}_5^{+}$

Answer 1

Answer: (B), (C)

$N{O}_2^{+},C{H}_3^{+},C{H}_3-C^{+}=O$

Electrophiles :

Electrophile : These are electron deficient species.

Types of electrophiles :

$1.$ Neutral molecules with vacant orbitals of central atom. Example: $B{F}_3,AlC{l}_3$ etc.

$2.$ Molecules with positive charge or free radicals on the central atom. Example: $N{O}_2^{+},C{H}_3^{+},C{H}_3-C^{+}=O$ etc.

$3.$ Molecules with central atoms surrounded by more electronegative atoms with a double bond. Example: $C{O}_2,S{O}_3$ etc.

Thus, all the species in options $\left(B\right)$ and $\left(C\right)$ are electrophiles.

$H_{2}O$ and $N{H}_3$ are nucleophiles because of the presence of lone pairs.

$C_2{H}_5^{-}$is a nucleophile because of the presence of negative charge.

Hence, $\left(B\right)$ and $\left(C\right)$ are correct.