Amines model answers Flashcards
how can methylamine act as Bronsted-Lowry base?
Lone pair on N atom
is donated to H+ ion or is proton acceptor
Why is phenylamine weaker base than cyclohexylamine?
Lone pair on N
is less available or electron density lowered
Due to delocalisation or resonance
Explain how the buffer solution is able to resist a change in pH when a small amount of NaOH is added
extra OH- reacts with (positive ion)
ratio of salt to base remains almost constant
What feature of ammonia molecule allows it to act as a base?
lone pair on N
Why is methylamine a stronger base than ammonia?
inductive effect of CH3 OR electron donation
increases electron density of N OR makes lone pair more available
where is the fingerprint region?
1500-500 cm-1
How can infrared spectra outside fingerprint region be used to differentiate between tertiary and secondary amines?
Absorption/trough/peak/spike at 3300-3500cm-1
N-H bond only present in secondary amine/not present in tertiary amine OR N-H peak only present in spectrum of secondary amine/not present in spectrum of tertiary amine
Disadvantage of amine synthesis via nucleophilic substitution then reduction
Lower yield because 2 steps
hydrogen is flammable and explosive
Toxic/poisonous KCN or HCN or cyanide
Expensive LiAlH4
Disadvantage of amine synthesis via nucleophilic substitution
Further reaction/substitution likely
Suggest reason for difference between experimental and actual value of x in Na2CO3.xH2O
Failure to drive off all of the water
Failure to heat for long enough
Not heated to constant mass
Uses of quaternary ammonium salts
Manufacture of detergents
Fabric softener
Cationic surfactant
Conditions for réduction using hydrogen
High temp
High pressure
Conditions for réduction using LiAlH4
Dissolved in ether
Reagents and conditions for reduction of nitrobenzene
Concentrated HCl
Tin catalyst
High temp
High pressure
How to make a basic buffer using an amine
Mix amine with its salt
