Video: Relative reactivity of lithium and sodium with water
Lithium is added to water containing phenolphthalein indicator. The water turns the characteristic purple color of the base form of the indicator.2 Li(s) + 2 H2O(l) ® 2 LiOH(aq) + H2(g)
The experiment is repeated with sodium. The reaction is more rapid. Also, the heat of reaction is sufficient to melt the sodium giving a globule of molten sodium skittering around.
2 Na(s) + 2 H2O(l) ® 2 NaOH(aq) + H2(g)