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The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
The test was reported in 1930 and became a standard method in qualitative organic chemistry. [2] The test has since become somewhat obsolete with the availability of various spectroscopic and chromatographic methods of analysis. It was named after Howard Lucas (1885–1963).
Zinc hydroxide Zn 2 is an inorganic chemical compound. It also occurs naturally as 3 rare minerals: wülfingite (orthorhombic), ashoverite and sweetite (both tetragonal). Like the hydroxides of other metals, such as lead , aluminium , beryllium , tin and chromium , Zinc hydroxide (and Zinc oxide ), is amphoteric .
Enthalpy change of solution in water at 25 °C for some selected compounds [2] Compound ΔH o in kJ/mol; hydrochloric acid: −74.84 ammonium nitrate +25.69 ammonia: −30.50 potassium hydroxide: −57.61 caesium hydroxide: −71.55 sodium chloride +3.87 potassium chlorate +41.38 acetic acid: −1.51 sodium hydroxide: −44.50
The conversion between hydroxyl value and other hydroxyl content measurements is obtained by multiplying the hydroxyl value by the factor 17/560. [2] The chemical substance may be a fat, oil, natural or synthetic ester, or other polyol. [3] ASTM D 1957 [4] and ASTM E222-10 [5] describe several versions of this method of determining hydroxyl value.
It can also be produced by the addition of hydrochloric acid to a hot, concentrated solution of mercury(I) compounds such as the nitrate: [2] Hg 2 (NO 3) 2 + 4 HCl → 2 HgCl 2 + 2 H 2 O + 2 NO 2. Heating a mixture of solid mercury(II) sulfate and sodium chloride also affords volatile HgCl 2, which can be separated by sublimation. [2]
Zinc oxide, ZnO, is the most important manufactured compound of zinc, with a wide variety of uses. [2] It crystallizes with the Wurtzite structure. It is amphoteric, dissolving in acids to give the aqueous Zn 2+ ion and in alkali to give the zincate (a.k.a. tetrahydroxozincate) ion, [Zn(OH) 4] 2−. Zinc hydroxide, Zn(OH) 2 is also amphoteric.
Several methods have been described for the production of aryl hydroxylamines from aryl nitro compounds: Raney nickel and hydrazine at 0-10 °C [15] Electrolytic reduction [16] Zinc metal in aqueous ammonium chloride [17] Catalytic Rhodium on carbon with excess hydrazine monohydrate at room temperature [18]