- The method of finding out exactly how much of each solution you will need to produce one of these salts is called a titration.
- The point at which an indicator changes colour during the titration is called the end point of the titration.
- Having found out how much acid and alkaline is needed, you redo the test, but without the indicator.
Making sodium sulfate crystals.
- 25cm^3 of sodium hydroxide is transferred to a conical flask using a pipette, and a few drops of methyl orange is added as indicator.
- Dilute sulfuric acid is run in from the burette until the indicator turns orange.
- The volume of each acid is noted, and the same amount of each are added into a conical flask without any indicator.
- The solution can be crystallised by evaporating it to the point the crystals will form on cooling.
Making sodium chloride crystals
- Using ammonia solution, rather than sodium, makes no different to the method used.
- Although simple ammonium salts don’t have water of crystallisation, you would still crystallise them slowly rather than evaporating them to dryness.
- Heating dry ammonium salts tend to break them up.
That is all!