Nucleophilic Substitution of Haloalkanes with Ammonia and Cyanide ion

Question 1

What happens in stage 1 when ammonia reacts with a haloalkane?

Answer 1

= in ammonia the nitrogen has a lone pair of electrons- nucleophile
= lone paur of electrons in nitrogen atom is attracted to the posiitve charge of the carbon electron defficnt atom
= nitrogen atom donates it’s lone pair of electrons to form a covalent bond with the carbon
= bond betwen carbon and bromine breaks electrons moving to the halogen
= we have a molecule of positive charge nitrogen atom and halide

Question 2

What happens in stage 2?

Answer 2

= a second molecule of ammonia removes a H+ ion fromthe nitrogen atom covalent bond between the hydrogen and nitrohe breaks with both electrons going to nitrohen
= made a

Question 3

What are the conditions for this reaction?

Answer 3

= warm haloalkane with a concentrated ammonia solution in ethanol
= carried out in asealed tube- increses pressure and prevents ammonia gas from escaping
= excess of amonia ia used- makes it more likely that the haloalkane reacts with ammonia rather than product amine

Question 4

What are the conditions needed for THe reavtion between a haloalkane and cyanide?

Answer 4

= mix the haloalkane with ethanol
= and aq solution of pottasium cyanaide and heat under reflux
=

Question 5

What does this reaction form?

Answer 5

= nitrile- prefix is carbon chain is one additional carbon
= useful: allows to increase the length of the carbon chain

Question 6

What happens when a cyanide reacts with a haloalkane?

Answer 6

= Cyanide has a lone pair of electrons with the carbon
= attracted to the positive charge carbon on haloalkane
= forms a covalent bond- carbon can have 4 so the carbon and bromine bond breaks- the eectrons go to the halogen
= produced is a nitrile molecle and a halide