Question

Rank order the following compounds according to base strength (weak to strongest): Ammonia,sodium hydroxide, sodium acetylide, tert-butyl lithium, sodium amide, methyl lithium. Explain if methyl lithium or tert-butyl lithium is the stronger base.

Answer 1

Ammonia is a weak base whereas sodium hydroxide is a strong one. Both sodium acetylide and sodiumamide are stronger bases than NaOH. Inoder to rank the given bases, consider the pk_a values.

Sodium hydroxide - 15

Sodium Acetylide - 25

Sodium Amide - 35

Ammonia - 9.25

Tert - butyllithium - 53

methyllithium - 48

Higher the pka value,higher is the basicity.

Thus the order is ,

Tert - butyllithium > methyllithium > Sodium Amide > Sodium Acetylide > Sodium hydroxide > ammonia