Salt can be separated from a salt-water mixture by using the principle of evaporation, with the help of a Bunsen Burner.
The following steps can be used to accomplish this:
- Mix some salt in water in a conical flask or beaker or any other glass equipment of your choice. This can be done by continuous stirring using a glass rod and can be aided by heating the water over Bunsen burner.
- Boil the salt-water mixture over Bunsen Burner till all the water evaporates.
- Allow the flask to cool down. You will find the salt as residue on the bottom of the flask.
We can also make this experiment more quantitative by asking the students to measure the quantity of salt present in samples of unknown salt concentration. For this, the student will measure the weight of the flask before adding the salt-water mixture to it and also after water evaporates and the flask cools down. The difference in the weight will be the weight of the salt. Knowing the volume of salt-water mixture and quantity of salt, we can also determine the salt concentration in our salt-water mixture.
hope this helps.