Halogenoalkanes

Question 1

define primary halogenoalkane

Answer 1

the carbon atom which carries the halogen atom is only attached to one other alkyl group

Question 2

define secondary halogenoalkane

Answer 2

the carbon atom which carries the halogen atom is attached directly to two alkyl groups

Question 3

define tertiary halogenoalkane

Answer 3

the carbon atom which carried the halogen atom is attached directly to three alkyl groups

Question 4

define nucleophile

Answer 4

species with a lone pair of electrons - can donate this pair of electrons

Question 5

name the nucleophilic substitution reactions

Answer 5

reactions with
- hydroxide
- water
- cyanide
- ammonia

Question 6

conditions for halogenoalkanes reacting with hydroxide ions and what is produced

Answer 6

• react with warm potassium hydroxide under reflux
• to produce alcohols

Question 7

in reaction with KOH what acts as a nucleophile

Answer 7

the OH- ion

Question 8

general equation for reaction of halogenoalkane + potassium hydroxide

Answer 8

R-X + KOH –> ROH + KX

Question 9

FLASHCARD (mechanism for reaction of bromoethane with hydroxide ions)

Question 10

general equation for halogenoalkane + water

Answer 10

R-X + H2O –> R-OH + H+ + X-

Question 11

what acts as a nucleophile in the reaction with water

Answer 11

water

Question 12

conditions for reaction with cyanide ions

Answer 12

• warm, under reflux
• KCN in ethanol (ethanolic solvent)

Question 13

why are the CN ions in an ethanolic solvent

Answer 13

• if in water, substitution may occur by OH- and not CN

Question 14

FLASHCARD (mechanism for reaction of bromoethane with cyanide ions)

Question 15

symbol + word equation (bromoethane + cyanide ions)

Answer 15

CH3CH2Br + KCN –> CH3CH3CN + KBr
bromoethane + potassium cyanide –> propanenitrile + potassium bromide

Question 16

usefulness of reaction with cyanide ions

Answer 16

• used to lengthen the carbon chain
• fairly easy to change the -CN into other groups

Question 17

conditions for reaction with ammonia

Answer 17

• warm, carried out in a sealed tube
• ammonia dissolved in ethanol solution (ethanolic solvent)
• excess ammonia

Question 18

FLASHCARD (mechanism for reaction of bromoethane + excess ammonia)

Question 19

what is a base

Answer 19

a proton acceptor

Question 20

what does the ammonia act as in the first and second reaction

Answer 20

first: nucleophile
second: base

Question 21

word and symbol equation for reaction of bromoethane with ammonia

Answer 21

CH3CH3Br + 2NH3 –> CH3CH2NH2 + NH4Br
bromoethane + ammonia –> ethylamine + ammonium bromide

Question 22

FLASHCARD (mechanism for reaction of bromoethane + water)

Question 23

what type of reaction is the reaction with aqueous OH-

Answer 23

nucleophilic substitution

Question 24

what type of reaction is the reaction with ethanolic OH-

Answer 24

elimination

Question 25

what does the OH- act as in the reaction with ethanolic OH-

Answer 25

a base