Question

Potassium reacts with water to produce _______ flame.

Answer 1

Flame

• Potassium reacts with cold water and gives potassium hydroxide and hydrogen gas

$\underset{\mathrm{Potassium}}{2\mathrm{K}\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Potassium}\mathrm{hydroxide}}{2\mathrm{KOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$

• The reaction is so vigorous that the evolved hydrogen catches fire spontaneously.

Therefore, potassium burns in water with a lilac-coloured flame.