Making sodium, potassium and ammonium salts
1 mark · EasyExplain why the titration method must be used when preparing sodium salts from an acid and an alkali.
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Because all sodium salts are soluble, so any excess solid would dissolve and cannot be filtered off, making it impossible to see when neutralisation is complete without titration.
Also accept: Because you cannot filter off excess solid since sodium compounds dissolve, so you need titration to know when neutralisation is complete.; You cannot tell when all the acid is neutralised without using an indicator, because excess solid dissolves.
Common mistakes: Stating only that sodium salts are soluble, without linking to why titration is needed.
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Marking points
B1 · 1 mark · States titration is needed because sodium salts are soluble and cannot filter off excess solid, so cannot see endpoint without indicator.
Worked solution
All sodium salts are soluble, so if you add excess solid during the preparation, it will dissolve and you cannot filter off the excess. Therefore, titration is required to determine the exact point of neutralisation.