Question

Which reagent is a good nucleophile

a. Nh3

b. Hbr

c. Br2

d. Bh3?

Answer 1

$nh3$


NH3 has a lone pair .. 5 N electrons combine with each of 3 H electrons leaving N's 2 electrons free !

Answer 2

Nh₃ (option a) is a good nucleophile compared to other mentioned in the given question.

• A nucleophile is a neutral or negatively charged species that tends to donate electrons to another atom to form a chemical bond. It is also called lewis base.

• The nucleophilicity of a reagent depends on its charge, electronegativity, steric hindrance, solvent.

• The lesser the electronegativity of the species, the better it tends to give away electrons.

• The higher the negative charge more is its nucleophilicity.

• NH₃ is a lewis base and has a lone pair of electrons.

• HBr has a lone pair of electrons but a poor tendency to donate electrons.

• Br₂ has a poor tendency to donate electrons.

• BH₃ is lewis acid and is an electrophile.

• Hence, we can conclude that NH₃ is a good nucleophile.