CP 6 - Chlorination of 2-methylpropan-2-ol with concentrated hydrochloric acid
On this page
In Edexcel Core Practical 6: Chlorination of 2-methylpropan-2-ol with concentrated hydrochloric acid, a reaction to form 2-chloro-2-methylpropane is carried out.
The crude product is separated, washed, and dried to isolate the chloroalkane, with the presence of chlorine confirmed using tests such as the addition of aqueous silver nitrate.
In Edexcel core practical 6: Investigating chlorination of 2-methylpropan-2-ol, there are several important safety requirements to be aware of (beyond normal lab practice such as wearing goggles).
- 2-methylpropan-2-ol and 2-chloro-2-methylpropane are both flammable – avoid naked flames.
- Calcium chloride is an irritant.
- Concentrated hydrochloric acid is corrosive and the fumes it produces are toxic and corrosive – carry out this practical in a fume cupboard or well-ventilated room.
Vapour can be produced when volatile substances are mixed in a separating funnel.
The distillation process requires careful setup to avoid loss of product or accidents.
Further tests can be done on the distillate to confirm the presence of 2-chloro-2-methylpropane.
After adding 5 cm3 of ethanol, 1 cm3 of aqueous sodium hydroxide, and warming the mixture in a water bath, a hydrolysis reaction occurs, releasing the chloride ions.
Adding excess nitric acid and a few drops of silver nitrate solution, a precipitate of silver chloride will form if the chloroalkane is present. The silver chloride precipitate appears as a white solid.