Zusammenfassung der Ressource
Lithium, sodium and
potassium with water
- Lithium
- The reaction generates heat too slowly and
lithium's melting point is too high for it to melt
- Lithium's density is only about half that of water so it floats on the surface
- It gently fizzes and gives off hydrogen
- It gradually reacts and disappears
- It forms a colourless solution of lithium hydroxide.
- Sodium
- Sodium floats on the surface of the water
- Because it has a low melting point it melts
- It forms a small silvery ball that
dashes around the surface.
- A white trail of sodium hydroxide is
seen in the water under the sodium
- This soon dissolves to give a colourless
solution of sodium hydroxide.
- Pottasium
- Potassium behaves rather like sodium
except that the reaction is faster
- Enough heat is given off to set light to the hydrogen.
- The normal hydrogen flame is
contaminated by potassium compounds...
- ...and so is coloured lilac (a faintly bluish pink).