Sodium From Seawater

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)
  • tape
  • plastic bottle
  • knife
  • gloves
  • tube
  • NaOH (optional)
  • Salt (optional)
  • 2 screws
  • Oil
  • 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.

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