Amines

Question 1

Why is butylamine a stronger base than ammonia

Answer 1

The alkyl group donates electrons to the lone pair on the nitrogen making it more electron dense and better at attracting protons

Question 2

Why is phenylamine a weaker base than ammonia

Answer 2

The lone pair on the nitrogen overlaps with the delocalised pi ring of the benzene group, reducing the electron density of the lone pair

Question 3

When does a positive ion form

Answer 3

At a low pH

Question 4

When does a negative ion form

Answer 4

At a high pH

Question 5

At what pH can an amino acid act as an acid?

Answer 5

At the isoelectric point the -NH3+ group can donate a proton; at lower pH values the -COOH group can also donate a proton

Question 6

At what pH can an amino acid act as a nucleophile?

Answer 6

A nucleophile has a lone pair on the
N. This only occurs at higher pH values