Potassium

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)

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)

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)

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

2 K(s) + H₂(g) 2 KH(s)

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

2 K(s) + 2 H₂O(l) 2 KOH(aq) + H₂(g)

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