The next investigation was the hydrolysis of primary, secondary and tertiary haloalkanes. By using hydrolysis the discovery of the unknown halgenoalkane was identified. This is done by a substitution reaction to produce halide ions, and then mixed with a silver nitrate solution to test the halogen itself.
Firstly, all the halogenoalkane must be transformed through a nucleophilic substitution reaction, this is done by heating it in a solution of ethanol and water, dissolving it into a mixture. Next, the halogen will be displaced by the OH group from the water molecules, acting as a nucleophile. The silver nitrate is used to detect which halide ions are present within the mixture.
Forming coloured precipitates with each mixture. A solution of ethanol and water was added to three test tube (5cm3 of ethanol and cm3 of water). Four drops of a specific primary haloallkanes (1-iodobutane, 1-chlorobutane and 1-bromobutane) were then added to the tubes , a different test tube for each haloalkane. Placing a bung in the top of the tube as they are placed in the water bath, this is so no vaporised product can escape from the mixture and the halide ions can be of a higher concentration. At this point three sets of 5cm3 of silver nitrate should also be placed in the water bath at the same temperature of 50?C.
Record the time it takes for the precipitate to fully form. Once the solution of haloalkane and ethanol have reached the same temperature of the water bath the silver nitrate is added. The bung should be placed straight in and a stop watch should be started.
The time shows how reactive the halide ions are and the strength of the carbon-halogen bone, as the weaker the bond is the quicker the compound would react. However, it does go through a two step reaction. Firstly, the haloalkane will react with the water to form butanol and a halogen acid. The halogen acid is then what is reacted with the silver nitrate, this creates a silver-halogen salt and nitric acid.