Topic 6: Halogenoalkanes

Question 1

Ozone depletion points

Answer 1

• Oxone is made of oxygen atoms
• Too much of it at ground level causes lung irritation and the degrading of plastics
• Protects the Earth from harmful exposure to too much UV radiation
• Without this, lots of ecosytems would fail

Question 2

Ozone breakdown equations

Answer 2

Cl* + O3 –> ClO* + O2

ClO* + O3 –> 2O2 + Cl*

Question 3

Nucleophile properties

Answer 3

• Have a lone (unshared) pair of electrons which can be used for a covalent bond
• The lone pair is situated on an electronegative atom

Question 4

Nucleophilic substitution mechanism (Words)

Answer 4

• Lone pair is attracted to delta positive carbon- The carbon has a full oputer shell.
• The nucleophile kicks the halogen off and forms a covalent bond with the carbon

Question 5

Why does rate of hydrolysis go down as you go up a group?

Answer 5

The bond enthalpies goes up due to:
Less sheilding
Lower atomic radius

Question 6

Nucleophilic substitution conditions

Answer 6

Reaction is at room temp
Reagests not dissolved in ethanol
Water present

Question 7

Nucleophilic elimination conditions

Answer 7

Reaction is hot
Reagesnts are dissolved in ethanol
No water present

Question 8

Nucleophilic elimination mechanism (words)

Answer 8

The OH ion uses lone paie to form bond with hydrogen on carbon next to halogen
The elecrons are then used to form a C=C double bond
As carbon is too full of electrons, the halogen is kicked off with the lone pairs of electrons.