1. CFCs & OTHER USES OF HALOgenoALKANES

2. Starter
Gethin produces chloroethane, bromoethane and iodoethane in an experiment but forgot to label his test tubes. Typical Gethin. Devise a method for identifying the correct test tubes. Include any results you would expect to find.

3. Helping out Gethin Steps:
Add sodium hydroxide (NaOH) to perform a nucleophilic substitution reaction.
Add dilute nitric acid (HNO3) to neutralise the mixture
Add silver nitrate (AgNO3) to create a precipitate
A further test can be done with ammonia (NH3) to be completely sure.
Halogen in halogenoalkane
Addition of Ag+(aq)
Addition of NH3 (aq) to precipitate formed
Chlorine
White precipitate
Dissolves in dilute NH3
Bromine
Cream precipitate
Dissolves in conc NH3
Iodine
Yellow precipitate
Does not dissolve in NH3

4. Uses of Halogenoalkanes
Solvents - Halogenoalkanes contain a polar section (carbon halogen bond) and non-polar region (presence of alkyl chain).
Can mix with polar and non-polar organic substances so therefore useful as solvents.
Non-flammable – dry cleaning and other processes involving degreasing.
Examples include tetrachloromethane CCl4 and tetrachloroethene, CCl2=CCl2

5. Uses of halogenoalkanes
Anaesthetics – halogenoalkanes are often used before surgical procedures as ‘knock out’ drugs.
Trichloromethane CHCl3 (chloroform).
‘Mickey Finn’ – 2,2,2-trichloroethane-1,1-diol, CCl3CH(OH)2 (choral hydrate).
Halothane, CF3CHBrCl still used.

6. USES of halogenoalkanes
Task:
Highlight any key points
Create paragraph headings
Answer the knowledge check questions at the bottom.