Halogenoalkanes Flashcards
What is a nucleophile?
Lone pair donator.
This means it is either a negative ion or a 𝛿- charge. .
It has a lone pair of electrons.
The lone pair is on an electronegative atom.
What is a reaction mechanism?
A series of steps.
The mechanism shows a general route taken by typical compounds.
The mechanism are named according to the type of substance and how it reacts:
Addition/substitution
Nucleophile/electrophile/free-radical
What undergoes nucleophilic substitution?
A halogenoalkane.
What do the ‘curly arrows’ show?
The movement of the pair of electrons.
What are the lone pairs of the nucleophile attracted to?
They are attracted to the electron deficient carbon.
What does the rate of substitution depend on?
The C - X bond strength.
What are the conditions for NaOH?
NaOH - nucleophile :OH-
Aqueous and warm
What are the conditions for KCN?
KCN - nucleophile :CN-
Ethanolic, warm
What are the conditions for the NH3?
NH3 - nucleophile :NH3
Excess concentrated ammonia dissolved in ethanol at pressure in sealed container.
What is an acid?
Proton donator
What is a base?
Proton acceptor
What is an alkali?
Soluble base
What does it mean because nucleophiles have lone pair donatorss?
It means that they can form dative bonds with H+. They are bases.
What are the conditions for an elimination reaction?
Heat
Ethanol as a solvent (no water present)
Concentrated potassium hydroxide
What happens to OH- under different conditions?
It will act as a base.
This will remove H+ from the halogenoalkane.
This is an elimination reaction rather than substitution.
