Question

Of the species listed below, select those less basic than acetylide (only one option permitted).
a. BuLi
b. NaNH2
c. NaOCH3
d. both BuLi and NaOCH3
e. both NaNH2 and NaOCH3
Give a explanation please

Answer 1

Answer on Question #63857 - Chemistry – Inorganic Chemistry

Of the species listed below, select those less basic than acetylide (only one option permitted).

a. BuLi

b. NaNH₂

c. NaOCH₃

d. both BuLi and NaOCH₃

e. both NaNH₂ and NaOCH₃

Give a explanation please

Solution.

The weaker the acid, the stronger the conjugate base

BuLi – a strong base (superbase), because butane has a pKₐ = 60 and conjugate base – butyl carbanion (CH₃CH₂CH₂CH₂⁻) has a pK_b = pK_w – pK_a = –46

NaNH₂: NH₂⁻ anion is the conjugate base of ammonia (NH₃). Since NH₃ has a pKₐ = 35, NH₂ is a strong base (pK_b = –21)

CH₃O⁻ anion is the conjugate base of methanol (CH₃OH). pKₐ(CH₃OH) = 15 and pK_b(CH₃O⁻) = –1

Acetylide C₂H⁻ has pK_b = –11 (pKₐ = 25)

The correct answer: c. NaOCH₃

Answer: c. NaOCH₃

http://www.AssignmentExpert.com