Haloalkanes Flashcards

1
Q

What are haloalkanes?

A

Organic compounds that contain carbon atoms and at least one halogen atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Are haloalkanes soluble in water?

A

Insoluble as C-H bonds are non polar and not compensated enough by C-X polarity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of intermolecular forces do haloalkanes have?

A

London forces and permanent dipoles between C-X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When would haloalkanes have higher boiling points?

A

Increased carbon chain length or a halogen further down group 7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the most important factor in determining halogen reactivity?

A

The strength of carbon-halogen bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What would bond polarity suggest the order of reactivity would be?

A

C-F would be most reactive as its the most polar bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What would bond enthalpies suggest the order of reactivity would be?

A

C-I would be the most reactive as it has the lowest bond enthalpy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define nucleophile

A

Electron pair donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give 3 examples of nucleophiles

A

:OH-
:CN-
:NH3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is nucleophilic substitution?

A

A reaction where a nucleophile donates a lone pair of electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is hydrolysis?

A

A reaction where water is a reactant that causes the breaking of a bond in a molecule (NaOH or KOH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What fission does water undergo to produce OH-

A

Heterolytic fision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why does the hydrolysis of 1-chlorobutane react the slowest?

A

Because the C-Cl- bond is the strongest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are CFCs?

A

Haloalkanes containing C, F and Cl only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the problem with CFCs?

A

They catalyse the breakdown of ozone in the atmosphere via free radical substitution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the main function of the ozone layer?

A

Provides protection from harmful UV radiation

17
Q

How does O3 form initially?

A
  • Ozone has a delicate equilibrium
  • Initially UV breaks O2 = O•
  • O2 + O = O3
  • Ozone rate of formation is the same as it breaks down
18
Q

Why are CFCs very stable?

A

Because of the strength of the carbon-halogen bonds within their molecules

19
Q

How do CFCs form radicals once it reaches the stratosphere?

A

UV radiation provides sufficient energy to break a carbon-halogen bond by homolytic fission, the Cl-Cl bond has the lowest enthalpy so is the bond that breaks

20
Q

Draw the mechanism to show the depletion of Cl• to the ozone layer

A

Cl2 = 2Cl•
Cl• + O3 = ClO• + O2
ClO• + O = Cl• + O2
2Cl• = 2Cl2