The reaction is slower than that of rubidium (immediately below potassium in the periodic table), but faster than that of sodium (immediately above potassium in the periodic table). The metal self-ignites, which also ignites the hydrogen gas. It moves around very quickly on the surface of the water. Early in the reaction, the potassium metal becomes so hot that it catches fire and burns with a characteristic pale lilac colour. When potassium is added to water, the metal melts and floats. The resulting solution is basic because of the dissolved hydroxide. The reaction continues even when the solution becomes basic. Potassium metal reacts very rapidly with water to form a colourless basic solution of potassium hydroxide (KOH) and hydrogen gas (H 2). Potassium metal dissolves readily in dilute sulphuric acid to form solutions containing the aquated K(I) ion together with hydrogen gas, H 2.ĢK(s) + H 2SO 4(aq) → 2K +(aq) + SO 4 2-(aq) + H 2(g) Reaction of potassium with bases So, it reacts with fluorine, F 2, chlorine, Cl 2, bromine, I 2, and iodine, I 2, to form respectively potassium(I) bromide, KF, potassium(I) chloride, KCl, potassium(I) bromide, KBr, and potassium(I) iodide, KI.ĢK(s) + I 2(g) → KI(s) Reaction of potassium with acids

Potassium metal reacts vigorously with all the halogens to form potassium halides. Since there is an equal number of each element in the reactants and products of 2KCl + 2H2O Cl2 + H2 + 2KOH, the equation is balanced. Count the number of atoms of each element on each side of the equation and verify that all elements and electrons (if there are charges/ions) are balanced. The reaction is slower than that of rubidium (immediately below potassium in the periodic table), but faster than that of sodium (immediately above potassium in the periodic table).ĢK(s) + 2H 2O → 2KOH(aq) + H 2(g) Reaction of potassium with the halogens Step 4: Substitute Coefficients and Verify Result. Early in the reaction, the potassium metal becomes so hot that it catches fire and burns with a characteristic pale lilac colour. Potassium metal reacts very rapidly with water to form a colourless solution of potassium hydroxide (KOH) and hydrogen gas (H 2).

K(s) + O 2(g) → KO 2(s) Reaction of potassium with water If potassium is burned in air, the result is mainly formation of orange potassium superoxide, KO 2. However, this surface soon tarnishes because of reaction with oxygen and moisture from the air. The resulting surface is bright and shiny.

Potassium and water reaction