Haloalkanes

Question 1

what are the two types of reactions that haloalkanes will undergo

Answer 1

nucleophilic substitution and elimination

Question 2

what is a nucleophile

Answer 2

an electron pair donor

Question 3

what are the three types of nucleophilic substitution reactions with haloalkanes

Answer 3

• reaction with hydroxide ions
• reaction with sodium or potassium cyanide
• reaction with excess ammonia

Question 4

condition required for the reaction between a haloalkane and hydroxide ions

Answer 4

haloalkane must be warmed in aqueous solution of either NaOH or KOH

Question 5

haloalkane + OH- ->

Answer 5

alcohol and halide ion

Question 6

what do the sodium or potassium ions act as in the reaction between the haloalkane and the OH-

Answer 6

spectator ions

Question 7

conditions required for the reaction between a haloalkane and sodium or potassium cyanide

Answer 7

NaCN or KCN must be dissolved in ethanol and heated under reflux

Question 8

haloalkane + CN-

Answer 8

nitrile and halide ion

Question 9

how are the nitriles produced in the reaction between a haloalkane and cyanide turned into a carboxylic acid

Answer 9

reacting with HCl and Water (hydrolysis)

Question 10

nitriles+ HCl + water

Answer 10

C.acid and ammonium chloride

Question 11

what is hydrolysis

Answer 11

a reaction where a bond is broken by reacting it with H2O molecules

Question 12

haloalkane + 2NH3

Answer 12

amine and ammonium halide

Question 13

condition required for the reaction between a haloalkane and excess ammonia

Answer 13

heated in a sealed copper tube and needs excess of ammonia

Question 14

how is the reaction between chloro- bromo- and iodo-alkanes with water monitored

Answer 14

with silver nitrate solution - the silver ion displaces the hydrogen to form a silver halide. It is insoluble and due to the specific halogen on the halide, it has a specific colour

Question 15

what happens when silver nitrate solution is added to CH3CH2Cl + H2O

Answer 15

white precipitate formed

Question 16

what happens when silver nitrate solution is added to CH3CH2Br + H2O

Answer 16

cream precipitate formed

Question 17

what happens when silver nitrate solution is added to CH3CH2I + H2O

Answer 17

yellow precipitate formed

Question 18

does dilute NH3 redissolve AgI, AgBr or AgCl

Answer 18

AgI

Question 19

does conc NH3 redissolve AgI, AgBr or AgCl

Answer 19

AgBr and AgCl

Question 20

how does electronegativity change down Group 7

Answer 20

Gets less electronegative (Cl is more electronegative than I)

Question 21

how does bond strength change down group 7

Answer 21

decreases down the group

Question 22

how does reactivity change as you go down in group 7

Answer 22

increases

Question 23

condition required for the elimination reaction of haloalkanes

Answer 23

NaOH or KOH dissolved in ethanol (ethanolic)

Question 24

haloalkane + OH- (elimination)

Answer 24

alkene + water + halide ion

Question 25

what does the OH- ion behave as in an elimination reaction

Answer 25

a base (proton acceptor)

Question 26

why is ozone very useful high up in the atmosphere

Answer 26

it absorbs UV light that may cause skin cancer

Question 27

overall reaction when ozone is broken down into O2 molecules

Answer 27

2O3 -> 3O2

Question 28

why are HFCs less harmful that CFCs

Answer 28

dont contain any chlorine atoms and therefore cant produce any Cl. free radicals