Question

Each of these compounds can react as an electrophile. In each case, use curved arrows to show how the electrophile would react with strong nucleophile sodium ethoxide, Na^{+ -} OCH₂CH₃.

(a)

(b)

NH⁺₄

(c)

CH₃CH₂Br

(d)

BH₃

(e)

CH₃COOH

(f)

Short answer

(a)

(b)

(c)

(d)

(e)

(f)

Step-by-step solution

Lewis concept of acid and base

According to Lewis, an acid can be defined as any molecule, ion or radical which can accept one or more electron pairs, that is, an acid is an electron pair acceptor. A Lewis base can be defined as any molecule, ion or radical which can donate one or more electron pairs, that is, a base is an electron pair donor.

Electrophiles and nucleophiles

Lewis acid accepts a pair of electrons, hence it can be called as electrophiles which means electrons loving. Also, Lewis base donates a pair of electrons, hence it can be called as nucleophiles which means nuclei loving.

Curved arrow mechanism showing how the given compounds (electrophile) react with strong nucleophile sodium ethoxide,  Na+ - OCH2CH3.

Curved arrows are used to show the movement of electrons from the nucleophile (Lewis base) to the electrophile (Lewis acid).

(a)

(electrophile) (nucleophile)

(b)

(electrophile) (nucleophile)

(c)

(electrophile) (nucleophile)

(d)

(electrophile) (nucleophile)

(e)

(electrophile) (nucleophile)

(f)

(electrophile) (nucleophile)

(electrophile) (nucleophile)