Potassium Hydroxide KOH

Inorganic Compound of Class 12

Preparation

(i) It is prepared by electrolysis of an aqueous solution of potassium chloride in a cell similar to that used for NaOH.

KCl Potassium Hydroxide, KOH K+ + Cl−

At cathode: K+ + e−Potassium Hydroxide, KOH K

2K + H2O Potassium Hydroxide, KOH 2KOH + H2

At anode: Cl−Potassium Hydroxide, KOH Cl + e−

Cl + Cl Potassium Hydroxide, KOH Cl2↑

(ii) It can also be prepared by heating potassium carbonate will slaked lime (calcium hydroxide).

K2CO3 + Ca(OH)2Potassium Hydroxide, KOH CaCO3↓ + 2KOH

Properties

(i) It is a white crystalline solid which melts at 633 K.

(ii) It is more soluble in water than NaOH.

(iii) It is more soluble in alcohol than any other salt of potassium such as KCl, KNO3, K2SO4 etc.

(iv) It is a stronger base than NaOH.

(v) It has a strong corrosive action on skin.

Uses

(i) It is mainly used in the preparation of soft−soaps.

(ii) It is used for absorbing CO2 and SO2 in gas analysis.

(iii) Its aqueous and alcoholic solution is used for carrying out organic reactions since it dissolves both in water and alcohol.

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