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Sulfite ion reacts with mercury(II) ion in acid solution to form the mercury(I) ion. The reaction is rapid and quantitative. The mercury(I) ion absorbs at 237 nm with a molar
5. Beer's law Data for Sulfite Complexes of Covalent Mercury(II) Compounds
SO2 (ppm)?HgCl2a?HgBr2?Hg(Ac)2b?Hg(SCN)2
2.012,50010,00010,0009,200
4.012,50011,50010,0009,000
6.012,50011,50010,0009,200
8.012,00011,00010,5009,800
a
Molar absorptivity based on sulfite ion at 230 nm. Solution was 6.86 buffer.
b
Mercuric acetate solutions seemed to be somewhat unstable. absorptivity of about 25,000. The absorbance is linear over a range of approximately 0.5–5.0 ppm as SO2. Covalent mercury(II) compounds form a complex with sulfite, Hg(SO3)22?, which absorbs at 230 nm and shows a linear response over a range of 1–8 ppm as SO2.
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12.
CaO solubility in equimolar molten salts CaCl2x (x = 0, NaCl, KCl, SrCl2, BaCl2 and LiCl) was determined at 873–1223 K and activity coefficient calculated. CaO solubility in the binary salts is less than in CaCl2, and the activity coefficient is greater than one. With increasing temperature CaO solubility increases and the activity coefficient decreases. The dependency of CaO activity coefficient on temperature in equimolar molten salts CaCl2x is
CaCl2RTln γCaO = 6961 + 5.06 T (K)1123–1223 K
CaCl2–NaClRTln γCaO = 3985 + 17.67 T (K)923–1123 K
CaCl2–KClRTln γCaO = 2384 + 22.72 T (K)1073–1223 K
CaCl2–SrCl2RTln γCaO = 27245–1.13 T (K)1073–1223 K
CaCl2–BaCl2RTln γCaO = 17068 + 10.19 T (K)1223–1273 K
CaCl2–LiClRTln γCaO = 14724 + 0.72 T (K)923–1073 K
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13.
Cobalt ions in aqueous thiocyanate solution react with Aliquat-336-xylene solution to form anion-association complex which is easily extracted into the organic phase. A typical extraction procedure involves extracting a solution which is 10 ppm in cobalt and 0.06 M,
5. Stripping of Cobalt from 2% Aliquat-336-Xylene Solutions
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14.
A kinetic method is described for the determination of trace amounts of magnesium in the presence of calcium. The procedure is based on the inhibition of the manganese(II) catalyzed aerial oxidation of 1,4-dihydroxyphthalimide dithiosemicarbazone reaction by
2. Effect of Transition Metalsa
StrippantCobalt stripped (%)
Na2S (M) 1.018.3
2.010.7
Na2SO3 (M) 0.110.7
0.549.6
1.052.9
EDA (%) 2.576.6
NaOH (M) 0.14.1
0.574.1
1.090.8
2.076.8
NH4OH (M) 0.124.1
0.591.8
1.097.5
2.099.9
EDTA (M) 0.02>99.9
0.05>99.9
0.1>99.9
EDTA (%) 0.1>99.9
0.5>99.9
1.0>99.9
Transition metalConcentration (M)Percentage inhibitionMg(II) found (×l05M)
Fe(II)3.6.10?554.14.62
Fe(III)3.6.10?547.84.48
Co(II)3.4.10?550.04.53
Ni(II)3.4.10?550.04.53
Cu(II)3.1.10?552.04.56
Zn(II)3.0.10?554.14.62
Cd(II)1.7.10?552.04.56
Hg(II)9.9.10?645.84.44
Sn(II)2.1.10?650.04.52
Pb(II)1.2.10?654.14.62
a
Conditions: 4.53.10?5M Mg(II), 35 ng Mn ml?1, 0.429 M ammonia, 1.6.10?4M OH-PDT.
3. Determination of Magnesium in Natural Waters
Mg(II) found (M)b
Natural waterCa(II) presentaAtomic absorption
sampleMKinetic absorptionmethod
Commercial3.45 · 10?41.65 · 10?31.74 · 10?3
Commercial5.46 · 10?41.57 · 10?41.81 · 10?4
Untreated6.13 · 10?42.16 · 10?42.40 · 10?4
Treated4.95 · 10?41.93 · 10?42.17 · 10?4
a
EDTA titration less the magnesium.
b
Average of three separate determinations. traces of magnesium(II). The reaction is followed spectrophotometrically by measuring the rate of change in absorbance at 594 nm. The calibration graph (percentage inhibition vs magnesium concentration) is linear in the range 329–535 · 10?5M with an accuracy and precision of 1.2%. The method has been applied to the determination of magnesium in natural waters at low concentrations.
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15.
Rotational spectra have been assigned for four isotopic species of the linear HCN dimer in the vibrational ground state. The spectroscopic constants are
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16.
The oxidation of glycolaldehyde with hexaquomanganese(III) ions in a noncomplexing perchloric acid medium was studied. The optimum conditions have been found for analytical use of the reaction. The recommended procedure is based on the oxidation of the test substance with the oxidant in the absence of atmospheric oxygen and back-titration of the unconsumed reagent with ferrous sulfate.
2. Accuracy and Reproducibility of the Determination of Glycolaldehyde with Hexaquomanganese(III) Ions in a Noncomplexing Perchloric Acid Medium
isotope-B0 (MHz)DJ (kHz)xN1 (MHz)xN2 (MHz)
HC14N-HC14N1745.80973(50)2.133(30)?4.0973(200)?4.4400(190)
HC14N-HC15N1700.30190(30)1.939(40)?4.1059(10)-
HC15N-HC14N1729.92082(20)2.023(30)-?4.4339(6)
HC15N-HC15N1684.28825(25)1.900(30)--
Taken (μg)Found (μg)aStandard deviation (μg)
75174812
1501148515
225221927
a
The values are the average of seven determinations, from which the standard deviation value was calculated.
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17.
A potentiometric method is described for the determination of thiosemicarbazones involving the formation of a complex with Ag(I). This method is proposed for thiosemicarbazones of the following carbonyl compounds: salicylaldehyde, p-hydroxybenzaldehyde, benzaldehyde, picolinaldehyde, 6-methylpicolinaldehyde and p-dimethylaminebenzaldehyde. Stability constants of the complexes are determined by Ringbom and Harju's method.
FIG. 2. Variation of pAg + logαPAT (H) + log ([Ag?PAT)]/[PAT])
2. Formation Constants of the Silver-Thiosemicarbazonates
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18.
The Coulometrics Inc. CO2 coulometer has been shown to be an accurate and reliable CO2 measuring device. The coulometric efficiency is essentially 100%. This means that the method can be considered as a standard reference method for CO2. As with a CO2 absorption tube, certain potential interferences must be considered, however, the removal of these interferences is well documented in the literature.The CO2 coulometer has found a variety of applications in the author's
3. effect of flow rate on absorption of CO2 by coulometer
ThiosemicarbazoneLog Kf
-Benzaldehyde15.5 ± 0.1
-Picolinaldehyde14.0 ± 0.
-6-Methylpicolinaldehyde14.5 ± 0.
-Salicylaldehyde15.7 ± 0.1
-p-Hydroxybenzaldehyde15.6 ± 0.
-p-Dimethylaminebenzaldehyde17.2 ± 0.1
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19.
Cadmium ions react with the collector, ethylhexadecyldimethylammonium bromide (EHDABr), to form a surface-active sublate which can be removed from aqueous bromide
a. Effect of Foreign Metal Ions on the Flotation of Cadmiuma
CaCO3 (mg)C (mg)Flow rate (cm3/min)C found (mg)C (%)
27.9893.3591003.366912.03
28.6043.4322003.434312.00
29.2593.5113003.514912.01
33.8084.0574004.038111.94
5.6290.6755000.676012.01
10.3111.2375001.233711.96
15.6471.8785001.870611.95
35.2144.2265004.198211.92
40.7334.8885004.821211.84
59.6787.1615007.026311.77
30.3863.6467803.594111.83
29.7813.5747803.536111.87
28.1133.37411503.253411.57
Foreign ionForeign ion concentration (M) (×10?5)Foreign ion removed (%)Cadmium removed (%)
None99.21
Zn2+6.110.0698.41
Cu2+6.293.6497.80
Pb2+3.864.8091.78
Cr6+7.6930.7599.07 solutions by ion flotation. A typical ion flotation procedure involves passing air through a 250-ml solution containing 5 ppm Cd2+, 0.05 M Br?1, and 1.7 × l0?3M EHDABr at a flow rate of 40 ml/min for 1 hr. The procedure was simple and efficient. Chromium, copper, and zinc ions do not interfere under the experimental conditions.
a
Cd2+, 4.46 × 10?5M; EHDABr, 4.25 × 10?4; Br?, 5 × 10?2M; flow rate, 40 ml/min; time, 60 min.
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20.
By means of the CHEVENARD thermobalance, the precipitates used for the determination of chromium have been investigated and the following limits of temperature established:
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Precipitating reagentForm in which weighedTemperature limits
Ammonium hydroxide (to a chromic salt)Cr2O3> 812°
Ammonium hydroxide (to chromic acid)Cr2O3> 188°
Ammoniac (gas)Cr(OH)3440–475°
Ammoniac (gas)Cr2O3> 845°
AnilineCr2O3> 830°
HydroxylamineCr2O3> 850°
ThiosemicarbazideCr2Oa3.H2O380–410°
ThiosemicarbazideCr2O3> 475°
Potassium cyanateCr2O3.H2O320–370°
Potassium cyanateCr2O3> 473°
Ammonium nitriteCr2O3> 880°
Potassium iodo-iodateCr2O3> 850°
Disodium phosphateCrPO4> 946°
Silver nitrateAg2CrO492–812°
Mercurous nitrateHg2CrO482–256°
Mercurous nitrateCr2O3> 671°
Barium nitrateBaCrO4< 60°
Lead nitratePbCrO491–904°
8-HydroxyquinolineCr(C9H6ON)370–156°
8-HydroxyquinolineCr2O3> 500°
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