Rosemount Manual: Conductance Data for Commonly Used Chemicals | Rosemount Manuals & Guides

Conductance Data For Commonly
Used Chemicals

44-6039/rev. B
December 2010

1

CONDUCTANCE DATA FOR COMMONLY USED CHEMICALS

From an analytical point of view, little can be done with
a conductance reading, however accurate it may be,
unless it can be related to chemical concentration via a
table or graph. Much data has been generated in the
past 100 years in this area, but a comprehensive gath­ering of the information in a form useful to industry has
been lacking

1

. It is hoped that the following will provide
a ready and reasonably accurate reference of conduc­tance values for the majority of electrolytes encoun­tered in industrial situations.

The information is presented in graphical form to per­mit rapid evaluation of response patterns and to elimi­nate the time consuming and often impractical
(because of non-linearity) extrapolation required in
tables with widely separated concentrations. This
method of presentation sacrifices the precision gained
by listing actual values, but the accuracy retained is
more than sufficient for the great majority of industrial
uses. The intent has been to provide a useful working
tool more so than a scientific reference.

Most of the data presented is the result of extremely
careful and accurate laboratory work conducted by
various researchers over the years. It is recognized
that older sources of information, notably the extensive
International Critical Tables, have been found to be
slightly inaccurate due to changes in the definition of
basic units in recent times as well as to erroneous
alignment procedures and measurement techniques.
However, with the previously stated area of application
in mind, these minor errors are of little significance and
may safely be ignored.

A few curves are based on more casual “field condi­tion” observations, and others are derived from data
with a low degree of resolution in the original refer­ence. Both will be marked with a single asterisk (*) in
the index that follows.

All conductance values have been referenced to a sin­gle temperature of 25°C for convenience (isothermal
plots are given for selected chemicals of major impor­tance). Much of the original data was presented at this
temperature, and all sources fell in the range of 15° to
25°C. Where possible, the temperature correction fac­tor was calculated from isothermal equivalent conduc­tances listed in the International Critical Tables. An
average was taken over as wide a range as possible
from .5N to 5N and 0-25°C. When such a calculation
was not possible, the widely accepted “average” of
2%/°C was used. Temperature factors, of course, will
vary in a non-linear manner with respect to both tem­perature and concentration for many chemicals, but the
small size of the adjustments render this of little impor­tance. As the majority of corrections involved differen­tials of only 5° or 7°C, errors introduced from this
source will be small. With this in mind, the final effect of
temperature correction error deserves further com­ment.

The relative conductance values at various concentra­tions would not be noticeably affected. The error could
be approximately but correctly described as relating to
the reference temperature rather than conductance.
Too much or too little correction simply means that the
curve shown is really that seen at 24° or 26° rather
than the indicated 25°. It is not anticipated that errors
will exceed the +

1° examples given in any except the

most unusual cases.

No guarantees of accuracy can be given, but most of
the data should easily fall within 5% of the correct
absolute value. The choice of curve shape through
data points will be a factor in some cases, and it is for
this reason that the points were clearly indicated.
(Some were omitted in the lower portions of the scale
for the sake of clarity.)

1

An earlier and excellent series of curves was published for this purpose by Industrial Instruments Inc. It provided
very detailed data for a half-dozen or so commonly used chemicals, and has been included in the list of reference
sources.

NOTES:

1. Concentration is expressed as % by Weight of the anhydrous substance.

2. Conductance units are µmhos/cm.

3. Plotted data points are indicated by circles.

1

2

SOURCES OF CONDUCTANCE DATA

1. International Critical Tables, Vol. Vl, pp. 230-258; McGraw Hill, 1929.

2. Handbook of Chemistry and Physics, 55th Edition: CRC Press, 1976.

3. Lange’s Handbook of Chemistry, 10th and 11 th Editions.

4. Graphs published by Industrial Instruments, Inc.; Cedar Grove, N.J.

5. Previously unpublished laboratory measurements performed at Uniloc, Inc., Irvine, Calif. 1970-1976.

6. Miscellaneous information regarding single electrolytes obtained from various reliable industrial sources.

7. Electrolyte Solutions, Robinson and Stokes: Butterworths, 1959.

8. Electrochemical Data, Dobos: Elsevier, 1975.

9. Electrolytic Conductance and the Conductances of the Halogen Acids in Water, Hamer and DeWane: National

Bureau of Standards Publication NSRDS-NBS 33, 1970.

10.Handbook of Electrochemical Constants, Parsons: Butterworths/Academic Press, 1959.

3

INDEX OF ELECTROLYTES

Maximum conductance and

Chemical

point of inflection at 25°C

Mol. Wt. Graph

Substance Formula

[

µmhos/cm/% by wt.]

(Anhydrous) No.

1. Acetic acid CH3COOH 1,850/17% 60.05 2

2. Aluminum chloride AlCl

3

— 133.34 6

3. *Ammonia/Ammonium Hydroxide NH3/NH4OH 1,200/5.5% 17.03/35.05 2

4. *Ammonium bifluoride NH4F•HF — 57.04 7

5. Ammonium chloride NH4Cl — 53.50 13

6. Ammonium fluoride NH4F — 37.04 7

7. Ammonium iodide NH4I — 144.94 14

8. Ammonium nitrate NH4NO

3

— 80.04 13

9. Ammonium sulfate (NH4)2SO

4

— 132.14 11

10. Ammonium thiocyanate NH4SCN — 76.12 10

11. Barium chloride BaCl

2

— 208.25 8

12. *Barium hydroxide Ba(OH)

2

— 171.39 4

13. *Barium nitrate Ba(NO3)

2

— 261.38 3

14. Cadmium bromide CdBr

2

30,000/32% 272.24 9

15. Cadmium chloride CdCl

2

35,000/22% 183.32 5

16. Cadmium iodide Cdl

2

366.25 9

17. Cadmium nitrate Cd(NO3)

2

108,000/32% 164.10 9

18. Cadmium sulfate CdSO

4

51,000/27% 208.48 9

19. Calcium chloride CaCl

2

204,000/24% 110.99 11

20. Calcium nitrate Ca(NO3)

2

122,000/25% 164.10 9

21. Cesium chloride CsCl — 168.37 13

22. Chromic acid CrO

3

670,000/35% 99.99 14

23. Citric acid (COOH)CH2C(OH)
(COOH)•H2O 7,900/20% 210.14 (Hyd.) 2

24. Cobaltous Chloride COCl

2

— 129.84 6

25. Cupric chloride CuCl

2

108,000/23% 134.45 11

26. Cupric nitrate Cu(NO3)

2

134,000/28% 187.55 8

27. Cupric sulfate CuSO

4

— 159.61 6

28. (Ethylenediamine) Tetraacetic acid

disodium salt, EDTA sodium Na2C10H14O8N2•2H2O — 372.24(Hyd.) 3

29. Ferric chloride FeCl

3

96,000/16% 162.22 9

30. Ferrous sulfate FeSO

4

53,000/24% 15.94 6

31. Formic acid HCOOH 11,500/30% 46.03 2

32. Hydrobromic acid HBr — 80.92 14

33. Hydrochloric acid HCl 850,000/19% 36.47 1

34. Hydrofluoric acid HF — 20.01 13

35. Hydroiodic acid HI — 127.93 14

36. Iodic acid HlO

3

— 175.93 12

37. Lactic acid CH3CHOH COOH 5,700/15% 90.08 2

38. Lanthanum nitrate La(NO3)

3

97,000/28% 324.93 8

39. Lead (plumbous) nitrate Pb(NO3)

2

— 331.23 8

40. Lithium chloride LiCl 190,000/21% 42.40 11

41. Lithium hydroxide LiOH 380,000/11% 23.95 13

42. Lithium iodide LiI — 133.86 7

43. Lithium sulfate Li2SO

4

83,000/18% 109.95 7

44. Magnesium chloride MgCl

2

160,000/18% 95.23 11

45. Magnesium nitrate Mg(NO

3)2

— 148.34 6

46. Magnesium sulfate MgSO

4

58,000/17% 120.37 7

47. Manganous chloride MnCl

2

130,000/20% 125.84 8

48. Manganous sulfate MnSO

4

51,500/22% 151.00 5

49. Nickel sulfate NiSO

4

— 154.78 7

50. Nitric acid HNO

3

865,000/29% 63.02 1

51. Oxalic acid HO

2

CCO2H — 90.04 4

52. Phosphoric acid H3PO

4

230,000/50% 98.00 12

53. Potassium acetate KCH

3CO2

150,000/32% 98.14 12

54. Potassium bicarbonate KHCO

3

— 100.12 7

55.Potassium biphthalate KHC8H4O

4

— 204.23 3

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INDEX OF ELECTROLYTES (Continued)

Maximum conductance and

Chemical

point of inflection at 25°C

Mol. Wt. Graph

Substance Formula

[

µmhos/cm/% by wt.]

(Anhydrous) No.

56. Potassium bromide KBr — 119.01 13

57. Potassium carbonate K

2CO3

258,000/34% 138.21 12

58. Potassium chloride KCl — 74.55 1

59. Potassium chromate K

2

CrO

4

— 194.20 10

60. Potassium cyanide KCN — 65.11 6

61. Potassium dichromate K2Cr2O

7

— 294.21 6

62. Potassium ferricyanide K

3

Fe(CN)

6

— 329.26 13

63. Potassium ferrocyanide K4Fe(CN)

6

— 368.36 6

64. Potassium fluoride KF 288,000/34% 58.10 12

65. Potassium hydroxide KOH 625,000/26% 56.11 14

66. Potassium iodide Kl — 166.03 14

67. Potassium nitrate KNO

3

— 101.10 7

68. Potassium oxalate K2C2O

4

— 166.22 7

69. Potassium permanganate KMnO

4

— 158.04 4

70. Potassium phosphate (monobasic) KH2PO

4

— 136.13 4

71. Potassium phosphate (dibasic) K2HPO

4

— 174.18 4

72. Potassium sulfate K2SO

4

— 174.26 4

73. Potassium sulfide K2S 535,000/30% 110.26 14

74. Potassium thiocyanate KSCN — 97.18 10

75. Procaine hydrochloride C6H4[COOCH2CH2N
(C2H5)2] (NH2)•HCI-1,4 34,000/32% 272.78 5

76. Sea water — — — 4

77. *Silver fluoride AgF — 126.88 10

78. Silver nitrate AgNO

3

— 169.89 12

79. Sodium acetate NaCH3CO

2

78,000/22% 82.04 5

80. Sodium bicarbonate NaHCO

3

— 84.01 3

81. Sodium bromide NaBr — 102.91 10

82. Sodium carbonate Na2CO

3

103,000/19% 106.01 6

83. Sodium chloride NaCl — 58.44 1

84. Sodium citrate Na3C6H5O

7

64,500/23% 258.07 5

85. Sodium diatrizoate (Hypaque) Na(CH3CONH)2C6l3CO

2

18,500/40% 635.92 5

86. Sodium dichromate Na2Cr2O

7

165,000/40% 261.97 9

87. Sodium ferrocyanide Na

4

Fe(CN)

6

— 303.92 10

88. Sodium hydroxide NaOH 410,000/15% 40.01 1

89. Sodium molybdate Na

2

MoO

4

— 205.95 4

90. Sodium nitrate NaNO

3

— 85.01 11

91. Sodium phosphate (monobasic) NaH2PO

4

60,000/28% 119.97 8

92. Sodium phosphate (dibasic) Na

2

HPO

4

— 141.98 3

93. Sodium phosphate (tribasic) Na

3PO4

— 163.96 4

94. Sodium sulfate Na2SO

4

— 142.07 7

95. Sodium sulfide Na

2

S 262,000/15% 78.06 10

96. Sodium tartrate NaOOC(CHOH)2COONa 68,500/24% 194.07 5

97. Sodium thiocyanate NaSCN 206,000/34% 81.08 12

98. Sodium thiosulfate Na

2S2O3

152,000/29% 158.13 8

99. Sodium tungstate Na

2WO4

— 293.92 4

100. Strontium chloride SrCl

2

198,000/30% 158.55 11

101. Strontium nitrate Sr(NO3)

2

113,000/30% 211.65 8

102. Sulfuric acid H

2SO4

825,000/30% 98.08 1

103. Tartaric acid HO

2

C(CHOH)2CO2H 11,800/24% 150.09 2

104. Tetracaine hydrochloride C

l5H24N2O2

•HCI — 300.84 4

105. Trichloracetic acid CCl3COOH — 163.38 10

106. Zinc chloride ZnCl

2

104,000/27% 136.29 12

107. Zinc Sulfate ZnSO

4

56,500/4% 161.44 4

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