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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
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SO2 (ppm) | ?HgCl2a | ?HgBr2 | ?Hg(Ac)2b | ?Hg(SCN)2 |
2.0 | 12,500 | 10,000 | 10,000 | 9,200 |
4.0 | 12,500 | 11,500 | 10,000 | 9,000 |
6.0 | 12,500 | 11,500 | 10,000 | 9,200 |
8.0 | 12,000 | 11,000 | 10,500 | 9,800 |
- 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.
12.
CaO solubility in equimolar molten salts CaCl2–x (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 CaCl2–x is
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CaCl2 | RTln γCaO = 6961 + 5.06 T (K) | 1123–1223 K |
CaCl2–NaCl | RTln γCaO = 3985 + 17.67 T (K) | 923–1123 K |
CaCl2–KCl | RTln γCaO = 2384 + 22.72 T (K) | 1073–1223 K |
CaCl2–SrCl2 | RTln γCaO = 27245–1.13 T (K) | 1073–1223 K |
CaCl2–BaCl2 | RTln γCaO = 17068 + 10.19 T (K) | 1223–1273 K |
CaCl2–LiCl | RTln γCaO = 14724 + 0.72 T (K) | 923–1073 K |
Full-size table
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,
Strippant | Cobalt stripped (%) | |||
Na2S (M) 1.0 | 18.3 | |||
2.0 | 10.7 | |||
Na2SO3 (M) 0.1 | 10.7 | |||
0.5 | 49.6 | |||
1.0 | 52.9 | |||
EDA (%) 2.5 | 76.6 | |||
NaOH (M) 0.1 | 4.1 | |||
0.5 | 74.1 | |||
1.0 | 90.8 | |||
2.0 | 76.8 | |||
NH4OH (M) 0.1 | 24.1 | |||
0.5 | 91.8 | |||
1.0 | 97.5 | |||
2.0 | 99.9 | |||
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 metal | Concentration (M) | Percentage inhibition | Mg(II) found (×l05M) |
Fe(II) | 3.6.10?5 | 54.1 | 4.62 |
Fe(III) | 3.6.10?5 | 47.8 | 4.48 |
Co(II) | 3.4.10?5 | 50.0 | 4.53 |
Ni(II) | 3.4.10?5 | 50.0 | 4.53 |
Cu(II) | 3.1.10?5 | 52.0 | 4.56 |
Zn(II) | 3.0.10?5 | 54.1 | 4.62 |
Cd(II) | 1.7.10?5 | 52.0 | 4.56 |
Hg(II) | 9.9.10?6 | 45.8 | 4.44 |
Sn(II) | 2.1.10?6 | 50.0 | 4.52 |
Pb(II) | 1.2.10?6 | 54.1 | 4.62 |
- a
- Conditions: 4.53.10?5M Mg(II), 35 ng Mn ml?1, 0.429 M ammonia, 1.6.10?4M OH-PDT.
Mg(II) found (M)b | |||
Natural water | Ca(II) presenta | Atomic absorption | |
sample | M | Kinetic absorption | method |
Commercial | 3.45 · 10?4 | 1.65 · 10?3 | 1.74 · 10?3 |
Commercial | 5.46 · 10?4 | 1.57 · 10?4 | 1.81 · 10?4 |
Untreated | 6.13 · 10?4 | 2.16 · 10?4 | 2.40 · 10?4 |
Treated | 4.95 · 10?4 | 1.93 · 10?4 | 2.17 · 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.
15.
Rotational spectra have been assigned for four isotopic species of the linear HCN dimer in the vibrational ground state. The spectroscopic constants are
isotope | -B0 (MHz) | DJ (kHz) | xN1 (MHz) | xN2 (MHz) |
HC14N-HC14N | 1745.80973(50) | 2.133(30) | ?4.0973(200) | ?4.4400(190) |
HC14N-HC15N | 1700.30190(30) | 1.939(40) | ?4.1059(10) | - |
HC15N-HC14N | 1729.92082(20) | 2.023(30) | - | ?4.4339(6) |
HC15N-HC15N | 1684.28825(25) | 1.900(30) | - | - |
Taken (μg) | Found (μg)a | Standard deviation (μg) |
751 | 748 | 12 |
1501 | 1485 | 15 |
2252 | 2192 | 7 |
- a
- The values are the average of seven determinations, from which the standard deviation value was calculated.
17.
Cadmium ions react with the collector, ethylhexadecyldimethylammonium bromide (EHDABr), to form a surface-active sublate which can be removed from aqueous bromide
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Foreign ion | Foreign ion concentration (M) (×10?5) | Foreign ion removed (%) | Cadmium removed (%) |
None | 99.21 | ||
Zn2+ | 6.11 | 0.06 | 98.41 |
Cu2+ | 6.29 | 3.64 | 97.80 |
Pb2+ | 3.86 | 4.80 | 91.78 |
Cr6+ | 7.69 | 30.75 | 99.07 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.
18.
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])
Thiosemicarbazone | Log | |||
-Benzaldehyde | 15.5 ± 0.1 | |||
-Picolinaldehyde | 14.0 ± 0. | |||
-6-Methylpicolinaldehyde | 14.5 ± 0. | |||
-Salicylaldehyde | 15.7 ± 0.1 | |||
-p-Hydroxybenzaldehyde | 15.6 ± 0. | |||
-p-Dimethylaminebenzaldehyde | 17.2 ± 0.1 |
CaCO3 (mg) | C (mg) | Flow rate (cm3/min) | C found (mg) | C (%) |
27.989 | 3.359 | 100 | 3.3669 | 12.03 |
28.604 | 3.432 | 200 | 3.4343 | 12.00 |
29.259 | 3.511 | 300 | 3.5149 | 12.01 |
33.808 | 4.057 | 400 | 4.0381 | 11.94 |
5.629 | 0.675 | 500 | 0.6760 | 12.01 |
10.311 | 1.237 | 500 | 1.2337 | 11.96 |
15.647 | 1.878 | 500 | 1.8706 | 11.95 |
35.214 | 4.226 | 500 | 4.1982 | 11.92 |
40.733 | 4.888 | 500 | 4.8212 | 11.84 |
59.678 | 7.161 | 500 | 7.0263 | 11.77 |
30.386 | 3.646 | 780 | 3.5941 | 11.83 |
29.781 | 3.574 | 780 | 3.5361 | 11.87 |
28.113 | 3.374 | 1150 | 3.2534 | 11.57 |
Precipitating reagent | Form in which weighed | Temperature limits |
Ammonium hydroxide (to a chromic salt) | Cr2O3 | > 812° |
Ammonium hydroxide (to chromic acid) | Cr2O3 | > 188° |
Ammoniac (gas) | Cr(OH)3 | 440–475° |
Ammoniac (gas) | Cr2O3 | > 845° |
Aniline | Cr2O3 | > 830° |
Hydroxylamine | Cr2O3 | > 850° |
Thiosemicarbazide | Cr2Oa3.H2O | 380–410° |
Thiosemicarbazide | Cr2O3 | > 475° |
Potassium cyanate | Cr2O3.H2O | 320–370° |
Potassium cyanate | Cr2O3 | > 473° |
Ammonium nitrite | Cr2O3 | > 880° |
Potassium iodo-iodate | Cr2O3 | > 850° |
Disodium phosphate | CrPO4 | > 946° |
Silver nitrate | Ag2CrO4 | 92–812° |
Mercurous nitrate | Hg2CrO4 | 82–256° |
Mercurous nitrate | Cr2O3 | > 671° |
Barium nitrate | BaCrO4 | < 60° |
Lead nitrate | PbCrO4 | 91–904° |
8-Hydroxyquinoline | Cr(C9H6ON)3 | 70–156° |
8-Hydroxyquinoline | Cr2O3 | > 500° |
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