POTASSIUM HYDROXIDE KOHProperties potassium hydroxide KOH: Caustic potash. White, very hygroscopic, melts and boils without decomposition. Readily soluble in water with a strong exothermic effect, creates a high alkaline environment. Exhibits properties of basic hydroxides (refers to alkali), neutralized by acids, reacts with oxides of nonmetals, amphoteric oxides and hydroxides. Vigorously absorbs moisture from the air and CO2. Reacts with non-metals, metals.
Obtaining potassium hydroxide KOH: 2 K + 2 H2O = 2 KOH + H2↑. 4 K + O2 + 2 H2O = 4 KOH. K2CO3 + Ca(OH)2 (saturated) = CaCO3↓ + 2 KOH. 2 KCl + 2 H2O → Electrolysis H2↑ (cathode) + Cl2(anode) + 2KOH, 2 KCl(melt) (on Hg-cathode)→Electrolysis→ 2K(cathode) + Cl2(anode). Chemical reactions with potassium hydroxide KOH: KOH·2H2O = KOH-H2O + H2O (33-40° C, vacuum), KOH·H2O = KOH + H2O (500° C, vacuum). KOH (diluted) + 6 H2O = [K(H2O)6](+) + OH(-). KOH + HCl (diluted) = KCl + H2O, KOH + HNO3 (diluted) = KNO3 + H2O. 2 KOH + H2SO4 (diluted) = K2SO4 + 2H2O, KOH + H2SO4 (conc., cold) = KHSO4 + H2O. KOH (diluted) + H3PO4 (conc.) = KH2PO4 + H2O, 2 KOH (diluted) + H3PO4 (diluted) = K2HPO4 + 2H2O. 3 KOH (conc.) + H3PO4 (diluted) = K3PO4 + 3H2O. KOH (diluted) + HF (diluted) = KF + H2O, KOH (conc.) + 2 HF (conc.) = KHF2 + H2O. KOH (conc.) + HCN = KCN + H2O. 2 KOH (conc., cold) + E2 = KEO + KE + H2O (E = Cl, Br, I), 6 KOH (conc., hot) + 3E2 = KEO3 + 5KE + 3H2O. 12 KOH (conc., hot) + 5 Cl2 + Br2 = 2 KBrO3 + 10 KCl + 6 H2O. 4 KOH + 4O3 = 4 KO3 + O2 + 2 H2O (to 20° C). 2 KOH + 2K = 2 K2O + H2 (400-450° C). 2 (KOH-2H2O) + 2 Al = 2 KAlO2 + 3 H2 + 2 H2O 2 KOH (conc.) + 6 H2O (hot) + 2 Al = 2 K[Al(OH)4] + 3 H2 ↑. 2 KOH (conc.) + EO2 = K2EO3 + H2O (E = C, S), KOH + EO2 = KHEO3↓ (in ethanol). 6 KOH (conc.) + 5 SiO2 = K4SiO4 (solution) + K2Si4O9 ↓ + 3 H2O. 4 KOH + 6 NO = 4 KNO2 + N2 + 2 H2O (400° C). 2 KOH (diluted) + 2 NO2 = KNO2 + KNO3 + H2O. 2 KOH (cold) + NO + NO2 = 2 KNO2 + H2O, 4 KOH (hot) + 4 NO2 + O2 = 4 KNO3 + 2 H2O. 2 KOH + Al2O3 = 2 KAlO2 + H2O (900-1100° C). KOH + Al(OH)3 = KAlO2 + 2 H2O (1000° C). 2 KOH (conc., hot) + 3 H2O + Al2O3 = 2K[Al(OH)4]. KOH (conc.) + Al(OH)3 = K[Al(OH)4]. KOH (conc.) + NH4Cl (conc.) = KCl + NH3 ↑ + H2O (boiling). 2 KOH + FeI2 = 2 KI + Fe(OH)2↓ (in atmosphere N2), 2 KOH (diluted) + 2 AgNO3 = Ag2O↓ + H2O + 2 KNO3. 3 KOH (diluted) + AlCl3 = Al(OH)3↓ + 3 KCl. 4 KOH (conc.) + AlCl3 = K[Al(OH)4] + 3 KCl. KOH (conc.) + 2 H2S + 4 SO2 = 3 K2SO3S + 5H2O. KOH + (2-4) H2O2 (conc.) →time→ K2O2·(2-4)H2O2↓ (0° C), K2O2·(2-4) H2O2 →time→ K2O2 + (2-4) H2O2 (over conc. H2SO4). 4KOH (melt)→Electrolysis→ 4K (cathode) + O2↑(anode) + 2H2O. |
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Air becomes liquid at about minus 190 degrees Celsius.