Organic Chem-haloalkanes

Question 1

Naming haloalkanes:

Answer 1

Halogens listen in alphabetical order, and positional numbers kept as low as possible

Question 2

Physical properties of haloalkanes

Answer 2

All similar but depends on halogens

None dissolve in water

Question 3

Which halogen is displayed easiest and why??

Answer 3

Iodine because it has the most shells between the nucleus and the electrons, and the weakest bond which is most easily broken, allowing a nucleophile to substitute into its place

Question 4

Why do boiling points of haloalkanes increase with molecular chain length??

Answer 4

A longer chain means more electrons, increasing the strength of temporary dipoles and therefore London forces

Question 5

Why has iodobutane got a higher boiling point than fluorobutane??

Answer 5

Although it is less polar and therefore has smaller permanent dipole attractions, the large increase in number of electrons outweighs this and so it has a higher boiling point due to increased London forces

Question 6

First stage of nucleophilic substitution with a OH- ion and bromoethane

Answer 6

Lone pair of electrons on hydroxide ion attacks positive polar end of carbon in the C-Br bond (double headed arrow). Shared electrons between the two go around to the other side of the negative polar end of the Br (double headed arrow)

Question 7

Second step of nucleophilic substitution of OH- and bromoethane

Answer 7

OH- ion is now attached to carbon, forming alcohol. Br- ion is left on its own