In this experiment we will make sodium from seawater. It is an experiment that will make students exited for chemistry. To make an explosive metal from just seawater. It is a relatively easy and cheap experiment that can be done in lab class.
Step 1: Materials
- Seawater (or just salt water)
- hot plate
- power supply (a 9v battery will work)
- graphite electrodes (can be obtained from a AA battery)
- plastic bottle
- NaOH (optional)
- Salt (optional)
- 2 screws
- Gas torch or Bunsen burner
- Small ceramic dish
Step 2: Set Up for Making NaOH Solution.
Caution this step will create chlorine gas. Which is very toxic. Perform this step outside or in a fume hood.
- Connect the graphite electrodes to the power supply.
- Cut two holes in the side of the bottle and one in the cap.
- Put the electrodes in the holes on the side, and the tube in the cap.
- Fill your bottle with salt water( I saturated my salt water with table salt ). Be sure that the electrodes are at least 1 cm submerged in the solution.
- Put the other side of the tube in a cup filed with water.
- Your setup will look something like seen in the picture. and you will be ready for the next step.
Step 3: Making NaOH
Caution Sodium hydroxide is a highly caustic base and alkali that decomposes proteins at ordinary ambient temperatures and may cause severe chemical burns. Now is a good time to put on your gloves.
- Start the electrolysis by turning on the power supply. I used 12 v 2 a.
- Now wait for the electrodes to stop bubbling.
- Empty your bottle in a heat resistant cup and boil the water off.
- There is your NaOH.
Step 4: Set Up for Making Sodium.
Caution Sodium is an explosive metal, do this step outside.
- Put all your NaOH in a small ceramic dish.
- If you did not get enough NaOH using the method above, add some pure NaOH (drain cleaner).
- Connect the 2 screws to the power supply and put them in the dish.
- Head up the NaOH with a torch until it melts at 323 °C (613 °F; 596 K).
- And turn on your power supply.
- If done well you are now making Sodium!
Step 5: Sodium
- You will see Sodium starting to form at the negative electrode.
- Some Sodium will burn up. But if you are quick you can pick up the Sodium with a glass rod or tube.
- Store this Sodium in oil because it can react with the moisture in the air.
- There is your Sodium your self made explosive metal extracted from sea water.
Step 6: Conclusion
I successfully made Sodium (a explosive metal) from sea water. It is quid interesting to see something so reactive be created from something so relaxing as sea water.