HALOGENOALKANES

Question 1

physical properties of halogenoalkanes

Answer 1

the C-X bond is polar because the halogen atom is more electronegative than the carbon atom
as we go down group 7 - the electronegativity of the X atom decreases
therefore the C-X bond becomes less polar

Question 2

first conclusion of boiling points

Answer 2

boiling point increase as the carbon chain length increases
VDW forces increase as relative molecular mass increases
so boiling point increases as the length of the carbon chain increases
evident in chloro, bromo and iodoalkanes

Question 3

second conclusion about boiling points

Answer 3

permanent dipole dipole interactions are greater the more polar the carbo-halogen bond
however, changing VDW forces have a greater effect on the boiling point of the molecule
as the Ar of the halogen increases for the same alkyl chain ,the boiling point increases

Question 4

solubility in water

Answer 4

carbon-halogen bond is quite polar
insoluble / sparingly soluble in water
soluble in organic solvents as can mix with other hydrocarbon molecules
used as dry cleaning fluids and degreasing agents