Question

Giving justification, categorise the following molecules/ions as nucleophile or electrophile:

$H{S}^{-},B{F}_3,C_2{H}_5{O}^{-}$
$(C{H}_3{)}_{3}N:,\stackrel{+}{Cl}$
$C{H}_3-\stackrel{+}{C}=O,H_{2}N{:}^{-},\stackrel{+}{N}{O}_2$

Answer 1

Nucleophile: A nucleophile is a reactant which gives an electron pair to form a covalent bond. A nucleophile is usually charged negatively or is neutral with a lone pair of electrons.

Nucleophiles: $H{S}^{-},C_2{H}_5{O}^{-},(C{H}_3{)}_{3}N,H_{2}N{:}^{-}$
These species have unshared pair of electrons, which can be donated and shared with an electrophile.

Electrophiles: Any molecule, ion or atom that is deficient in electron in some manner can act as an electrophile. They are generally positively charged or are neutral species (electron-deficient molecules) with empty orbitals.

Electrophiles: $B{F}_3,\stackrel{+}{Cl},\stackrel{+}{N}{O}_2,C{H}_3-\stackrel{+}{C}=O$
Reactive sites have only six valence electrons; can accept electron pair from a nucleophile.

Final Answer:
Nucleophiles: $H{S}^{-},C_2{H}_5{O}^{-},(C{H}_3{)}_{3}N,H_{2}N{:}^{-}$
Electrophiles: $B{F}_3,\stackrel{+}{Cl},\stackrel{+}{N}{O}_2,C{H}_3-\stackrel{+}{C}=O$