Question

Metal + Water (Cold) → Metal Hydroxide + Hydrogen

under this master equation,even potassium reacts na

Answer 1

Yes potassium also reacts.

Potassium is at the top of the reactivity series hence react readily (violently) with cold water forming hydroxides with the liberation of H2, the heat evolved is sufficient for the hydrogen to catch fire.

K(s) + 2H2O(l) → KOH(aq) + H2(g) + large amount of heat energy

catches fire