Jumping Sodium

Metallic sodium jumps between two immiscible liquids changing color of the water medium.ids

Scientific name: When sodium reaches the border between liquids it reacts with water producing sodium hydroxide and hydrogen.

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Chemistry experiment 11 - Jumping sodium

by koen2all

Прыгающий натрий - необычный химический опыт!

by Thoisoi

Safety

Wear eye protection goggles and gloves.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

2Na + 2H2O → 2NaOH + H2

Step-by-step instruction

  1. Prepare three volumetric cylinders.
  2. Pour about 150 ml of water to each cylinder.
  3. Add a few drops of thymolphtalein to the first cylinder, a few drops of phenolphthalein to the second one and some universal indicator to the last cylinder. The universal indicator changes its color to green (neutral medium).
  4. Add a small amount of vinegar to the last cylinder with universal indicator. The solution turns red.
  5. Carefully pour a layer of petrol to each of the cylinders. Avoid mixing the layers.
  6. Take out a piece of metallic sodium.
  7. Cut three small pieces (less than pea size) of sodium.
  8. Put them to the cylinders.
  9. Metallic sodium moves up and down in petrol layer and while reaching the border between liquids changes color of the water medium.

Scientific background

Sodium does not react with petrol but easily combines with water producing sodium hydroxide and hydrogen:

2Na + 2H2O → 2NaOH + H2

The hydrogen gas bubbles are formed when sodium touches the water, making the metal jump. Sodium hydroxide changes the pH of water to alkaline. This leads to consequent change of indicator color. It varies depending on the type of indicator: thymolphtalein becomes blue, phenolphthalein – pink, universal indicator turns color from red to violet.

Danger:
Coolness:
Difficulty:

Published on 17 January 2016

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst