haloalkanes

Question 1

3 ways haloalkanes can be made

Answer 1

1. alkanes - radical substitution
2. alkenes - electrophilic addition
3. alcohols - nucleophilic substitution

Question 2

why are haloalkanes generally more reactive than alkanes

Answer 2

the bond strength of the C-X bond is a lot weaker than a C-H bond so require less energy to break (exception of C-F bond)

Question 3

define electronegativity

Answer 3

the attraction between an atom and a shared pair of electrons

Question 4

what is the consequence of the C-X bond

Answer 4

it is polar

Question 5

what type of reaction is the hydrolysis of a haloalkane

Answer 5

a substitution reaction where the halogen is replaced by the -OH from the water

Question 6

how do you produce an alcohol from a haloalkane + what conditions are needed

Answer 6

hydrolysis of a haloalkane is a substitution reaction in which the halogen from the haloalkane is replaced by an -OH group of water
conditions - heat under reflux

Question 7

define reflux

Answer 7

the method used to continuously react volatile liquid whilst preventing their loss

Question 8

define nucleophile

Answer 8

an atom or group of atoms attracted to electron deficient centre

Question 9

mechanism involved in production of alcohol from haloalkane

Answer 9

nucleophilic substitution

Question 10

what type of bond fission is involved in nucleophilic substitution

Answer 10

heterolytic fission

Question 11

2 part reaction involved in measuring rate of hydrolysis of haloalkanes

Answer 11

1. nucleophilic substitution of haloalkane using water as a nucleophile
2. reaction between halide ion and silver ion to form silver halide

Question 12

use of the ethanol in reaction measuring rate of hydrolysis of haloalkanes

Answer 12

both water and the haloalkane dissolve in ethanol allowing them to mix

Question 13

use of the aqueous silver nitrate in reaction measuring rate of hydrolysis of haloalkanes

Answer 13

1. provides the water as the nucleophile for hydrolysis reaction
2. Ag+ ions allow to see when reaction has finished

Question 14

explain difference in rate of reaction of haloalkanes

Answer 14

1. chlorine slowest as it has the strongest bond enthalpy out of all halogens requires most energy to break
2. iodine quickest as bond strength weakest so requires less energy will react easier

Question 15

where is the ozone layer found

Answer 15

forms part of the stratosphere

Question 16

what causes the photodissociation of CFCs

Answer 16

uv light when in stratosphere - produces Cl radicals

Question 17

what does the Cl radical then do to ozone

Answer 17

ozone + oxygen radical –> 2x oxygen gas

Cl radical is a catalyst - isn’t used up