3.3.11 Amines

Question 1

Difference in base strength between ammonia, primary aliphatic and primary aromatic amines

Answer 1

Primary aliphatic - strongest base, alkyl groups push electrons onto attached groups so electron density increases which makes lone pair more available
Ammonia- doesn’t have aromatic group to pull lone pair of electrons away or alkyl groups to push forward
Primary aromatic- weak bases, benzene electrons drawn into itself, nitrogen base pair gets partially delocalised into ring so electron density on nitrogen decreases, lone pair less available

Question 2

Cationic surfactant properties + uses

Answer 2

Partially soluble and insoluble in water
Hydrocarbon chain insoluble in water- binds to grease
Polar head dissolves in water so grease can mix with water and be washed away
Detergent

Question 3

Describe what amines are

Answer 3

Organic compounds that contain nitrogen atoms with a lone pair. Derived from ammonia (NH3) in which one or more hydrogen atoms is replaced by an alkyl group

Question 4

Explain why amines behave as Brønsted-Lowry bases

Answer 4

Lone pair of electrons on nitrogen readily available to form diative bond with H^+

Question 5

Identify a substance that could be added to aqueous butylamine to produce a basic buffer solution

Answer 5

Strong acid / ammonium salt of a strong acid