Salt Preparation

Question 1

How do you prepare a salt from a solid base,carbonate or metal. [5]

Answer 1

1. Add the solid to the acid until no more reacts. heating maybe required.
2. Filter off the excess solid into an evaporating dish.
3. Evaporate the water by heating gently until the solution is ready to crystallize, i.e the solution is saturated with salt. This is the crystallization point.
4. Leave the solution to cool and form crystals.
5. Filter the crystals and leave them to dry.`

Question 2

How do you make a soluble salt from an alkali. [6]

Answer 2

1. Use a pipette to measure the volume of alkali-usually 25.0 cm3.
2. Put the alkali in a conical flask and add a few drops of indicator solution.
3. Fill a burette with acid and note the initial volume. Burettes measure the volumes of acids accurately.
4. Allow the acid to run into the conical flask until the indicator just changes color. This is the neutralization point. Note the final volume to find out how much acid has been used.
5. Repeat the steps 1-3 without adding indicator and use the burettes to deliver the exact volume of acid used in step 4.
6. Evaporate the solution to the crystallization point and allow to crystallize. Then, filter and leave the crystals to dry.

Question 3

How do you prepare an insoluble salt. [4]

Answer 3

1. Choose two solutions.
2. One should contain the metal ion(cation) of the salt that you preparing.
3. The other should contain the anion of the salt you are preparing.
4. Mix the the two solutions and the precipitate forms. This is an insoluble salt.
5. Filter to remove the solid insoluble salt.
   wash the salt with distilled water.
6. Leave the salt to dry on a filter paper.