Potassium hydroxide - KOH

What is Potassium hydroxide?

KOH is an inorganic compound with chemical name Potassium hydroxide. It is also called as Caustic potash or Lye or Potash lye and is a strong base. It is an alkali metal hydroxide. In its aqueous form it appears as a clear solution. In its solid form, KOH appears as a white to slightly yellow lumps, flakes, pellets, or rods without odour. This compound is soluble in water, freely soluble in ethanol, methanol, and glycerin. It is slightly soluble in ether. It is non-combustible but highly corrosive. It is widely used in chemical manufacturing, cleaning compounds, and petroleum refining.

Properties of Potassium hydroxide – KOH


Potassium hydroxide

Molecular weight/molar mass of KOH

56.11 g/mol

Density of Potassium hydroxide

2.044 g/cm3

Boiling Point of Potassium hydroxide

1,327 °C

Melting Point of Potassium hydroxide

360 °C

Potassium hydroxide structure – KOH

Potassium hydroxide structure

KOH Uses (Potassium hydroxide)

  • Potassium hydroxide solution is more conductive when compared to NaOH and therefore used as an electrolyte in alkaline battery.
  • It is used as a pH control agent in food industry.
  • It is used in thickening of food.
  • It is used in chip fabrication for semiconductors.
  • It is used in the manufacturing of cuticle removers which is used in manicure treatment.
  • It is used in the identification of species of fungi.
  • It is used in mercerizing cotton.
  • It is used in alkalimetric titrations in analytical chemistry.
  • Used in the manufacturing of liquid fertilizers.

Potassium hydroxide reactions

  • Reacts with CO2 to produce bicarbonate
  • KOH + CO2 → KHCO3

Health hazards

Potash lye and its solution can severely irritate skin, mucous membranes, and eyes. When it comes in contact with water or moisture it can generate heat to instigate combustible.

Learn more about the Structure, physical and chemical properties of KOH from the experts at BYJU’S.

Practise This Question

For the reaction 2NO(g)N2(g)+O2(g),ΔH=180 kJ mol1. Which of the following facts does not hold well?