Making Soluble Salts

Question 1

How can you make a soluble salt using an acid and a insoluble base ?

Answer 1

By reacting a acid and a insoluble base.

1. Heat acid in water bath, do this in fume cupboard
2. Add base to the acid, they will produce a soluble salt and water . You will know as the it will sink to the bottom
3. Filter until you have the salt and water
4. Heat solution to evaporate the water, allow the salt to crystallise and filter off

Question 2

How do you make a soluble salt using an acid /alkali reaction?

Answer 2

1. there is no finish signal , you can’t add an excess of alkali to the acid because the salt is soluble this would be contamination
2. Therefore you need to use the correct amount of alkali to neutralise , you use titration.
3. Measure amount needed - Pipette add indicator
4. Slowly add alkali using a Burette until the end point = neutralisation
5. Do the same without indicator - no contamination
6. The solution is salt and water only
7. Slowly evaporate to get crystals