Chemical reactions

Reaction of potassium with acids

Potassium dissolves readily in dilute sulphuric acid, forming potassium ions and hydrogen gas, H2.

2 K(s) + H2SO4(aq) 2 K+(aq) + SO42−(aq) + H2(g)

Reaction of potassium with air

Potassium reacts slowly with oxygen, O2, tarnishing the surface, under normal conditions.

If heated with a calculated amount of oxygen, potassium peroxide is formed [6]:

2 K(s) + O2(g) K2O2(s)

If heated with an excess amount of oxygen, potassium superoxide is formed [6]:

K(s) + O2(g) KO2(s)

Reaction of potassium with halogens

Potassium reacts with the halogens, forming the corresponding potassium halides.

2 K(s) + F2(g) 2 KF(s)
2 K(s) + Cl2(g) 2 KCl(s) [white]
2 K(s) + Br2(g) 2 KBr(s)
2 K(s) + I2(g) 2 KI(s)

Reaction of potassium with hydrogen

Potassium reacts with hydrogen, forming potassium hydride [6].

2 K(s) + H2(g) 2 KH(s)

Reaction of potassium with water

Potassium reacts wiolently with water, forming potassion hydroxide, KOH, and hydrogen gas, H2.

2 K(s) + 2 H2O(l) 2 KOH(aq) + H2(g)

Quantitative analysis

Method 3500-K C Inductively Coupled Plasma Method [1]. A portion of the sample is digested in a combination of acids. The digest is aspirated into an 8,000 K argon plasma where resulting light emission is quantified for 30 elements simultaneously.

Method limit of detection in water = 1.0 mg/L
Method limit of detection in soil = 100.0 mg/kg