Halogenoalkanes - Topic 6

to what three groups can halogenoalkanes be classified into

primary, secondary, tertiary

how many alkyl groups is the carbon bonded to in primary haloalkanes

1

how many alkyl groups is the carbon bonded to in secondary haloalkanes

2

how many alkyl groups is the carbon bonded to in tertiary haloalkanes

3

why are haloalkanes targets for nucleophiles

polar

why are halogenoalkanes polar

difference in electronegativity causing an uneven distribution of electrons

what happens in the hydrolysis of halogenoalkanes

the carbon halogen bond breaks in the presence of water

what does the hydrolysis rate of haloalkanes depend on

the bond enthalpy of the carbon halogen bond

does bond enthalpy increase or decrease down group 7

decrease

why does bond enthalpy decrease down group 7

atomic radius increases, carbon halogen bond length increases, electrostatic attraction decreases

which haloalkanes hydrolyse the fastest

Iodoalkanes

describe the steps in comparing reactivity of haloalkanes

1. put in test tube

2. add ethanol and heat in water bath

3. add silver nitrate solution

4. time how long it takes for ppt to form

what is the reactivity of primary, secondary, and tertiary haloalkanes

tertiary reacts the fastest, primary the slowest

why do tertiary haloalkanes react the fastest

form the most stable carbocations

what is a nucleophile

electron pair donator

what type of reactions do halogenoalkanes undergo

nucleophilic substitution

what do halogenoalkanes react with to form amines

excess ethanolic ammonia

what type of amines does the reaction between haloalkanes and ammonia form

primary

what reaction conditions are required for the reaction of halogenoalkanes and ammonia

heat and high pressure

what does the reaction of a halogenoalkane with ethanolic OH- form

alkene

what reaction conditions are needed for haloalkanes and ethanolic hydroxide

reflux

what type of reaction occurs between ethanolic hydroxide and halogenoalkanes

elimination

what is formed when halogenoalkanes react with hydroxides acting as a base

alcohols

what do halogenoalkanes react with to form nitriles

ethanolic KCN

what is the nucleophile in the reaction of halogenoalkanes to form nitriles

CN-

what does the formation of a nitrile do to the length of the carbon chain

extends it