Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish water, but less salty than brine. The salt concentration is usually expressed in parts per thousand (permille, ‰) and parts per million (ppm). The USGS salinity scale defines three levels of saline water. The salt concentration in slightly saline water is 1,000 to 3,000 ppm (0.1–0.3%); in moderately saline water is 3,000 to 10,000 ppm (0.3–1%); and in highly saline water is 10,000 to 35,000 ppm (1–3.5%). Seawater has a salinity of roughly 35,000 ppm, equivalent to 35 grams of salt per one liter (or kilogram) of water. The saturation level is only nominally dependent on the temperature of the water. At 20 °C (68 °F) one liter of water can dissolve about 357 grams of salt, a concentration of 26.3 percent by weight (% w/w). At 100 °C (212 °F) (the boiling temperature of pure water), the amount of salt that can be dissolved in one liter of water increases to about 391 grams, a concentration of 28.1% w/w.
Properties
| NaCl, wt% | Freezing point (°C) | Freezing point (°F) | Density (g/cm3) | Refractive index at 589 nm | Viscosity (cP ) |
|---|---|---|---|---|---|
| 0 | 0 | 32 | 0.99984 | 1.3330 | 1.002 |
| 0.5 | −0.3 | 31.46 | 1.0018 | 1.3339 | 1.011 |
| 1 | −0.59 | 30.94 | 1.0053 | 1.3347 | 1.02 |
| 2 | −1.19 | 29.86 | 1.0125 | 1.3365 | 1.036 |
| 3 | −1.79 | 28.78 | 1.0196 | 1.3383 | 1.052 |
| 4 | −2.41 | 27.66 | 1.0268 | 1.3400 | 1.068 |
| 5 | −3.05 | 26.51 | 1.0340 | 1.3418 | 1.085 |
| 6 | −3.7 | 25.34 | 1.0413 | 1.3435 | 1.104 |
| 7 | −4.38 | 24.12 | 1.0486 | 1.3453 | 1.124 |
| 8 | −5.08 | 22.86 | 1.0559 | 1.3470 | 1.145 |
| 9 | −5.81 | 21.54 | 1.0633 | 1.3488 | 1.168 |
| 10 | −6.56 | 20.19 | 1.0707 | 1.3505 | 1.193 |
| 12 | −8.18 | 17.28 | 1.0857 | 1.3541 | 1.25 |
| 14 | −9.94 | 14.11 | 1.1008 | 1.3576 | 1.317 |
| 16 | −11.89 | 10.60 | 1.1162 | 1.3612 | 1.388 |
| 18 | −14.04 | 6.73 | 1.1319 | 1.3648 | 1.463 |
| 20 | −16.46 | 2.37 | 1.1478 | 1.3684 | 1.557 |
| 23.3 | −21.1 | −5.98 | 1.179 | ||
| 26 | −19.18 | −2.52 | 1.193 | 1.3795 | 1.676 |
- At some ambient temperature
- At some ambient temperature
- At some ambient temperature (20°C)
- Eutectic mixture
At 100 °C (212 °F; 373 K), saturated sodium chloride brine is about 28% salt by weight. At 0 °C (32 °F; 273 K), brine can only hold about 26% salt. At 20 °C one liter of water can dissolve about 357 grams of salt, a concentration of 26.3%.
The thermal conductivity of seawater (3.5% dissolved salt by weight) is 0.6 W/mK at 25 °C (77 °F). The thermal conductivity decreases with increasing salinity and increases with increasing temperature. The salt content can be determined with a salinometer.
Density ρ of brine at various concentrations and temperatures from 200 to 575 °C (392 to 1,067 °F) can be approximated with a linear equation:
where the values of an are:
| Weight % | a2 | a3 |
|---|---|---|
| 5 | 0.043 | 72.60 |
| 10 | 0.039 | 73.72 |
| 15 | 0.035 | 74.86 |
| 20 | 0.032 | 76.21 |
| 25 | 0.030 | 77.85 |
Electrolysis
About four percent of hydrogen gas produced worldwide is created by electrolysis. The majority of this hydrogen produced through electrolysis is a side product in the production of chlorine.
- 2 NaCl(aq) + 2 H2O(l) → 2 NaOH(aq) + H2(g) + Cl2(g)
See also
- Brackish water
- Brine
- Salinity
- Seawater
References
- "Sodium Chloride MSDS". Sigma Aldrich. c. 2004. Archived from the original on 2021-02-09.
- Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton, Florida: CRC Press. pp. 8–71, 8–116. ISBN 0-8493-0486-5.
- CRC Handbook of Chemistry and Physics, 63rd Edition 1982-1983.
- "Solubility". University of Wisconsin Fundamentals of Chemistry. Archived from the original on 31 March 2016. Retrieved 6 November 2014.
- Thermophysical properties of seawater: a review of existing correlations and data Paper published in April 2010 on web.mit.edu. Retrieved 2021-03-11.
- https://handbook.ashrae.org/Handbooks/F17/SI/F17_Ch31/figures/F31sf08.jpg Plots of thermal conductivity vs. temperature for 0, 5, ... 25 w/w NaCl/water solutions. Retrieved 2020-11-27.
- "Thermal conductivity of seawater and its concentrates". twt.mpei.ac.ru. Retrieved 2018-02-16.
- Dittman, Gerald L. (February 16, 1977). "Calculation of Brine Properties". Lawrence Livermore Laboratories. Livermore CA. doi:10.2172/7111583.
External links
Media related to Saline water at Wikimedia Commons
Saline water more commonly known as salt water is water that contains a high concentration of dissolved salts mainly sodium chloride On the United States Geological Survey USGS salinity scale saline water is saltier than brackish water but less salty than brine The salt concentration is usually expressed in parts per thousand permille and parts per million ppm The USGS salinity scale defines three levels of saline water The salt concentration in slightly saline water is 1 000 to 3 000 ppm 0 1 0 3 in moderately saline water is 3 000 to 10 000 ppm 0 3 1 and in highly saline water is 10 000 to 35 000 ppm 1 3 5 Seawater has a salinity of roughly 35 000 ppm equivalent to 35 grams of salt per one liter or kilogram of water The saturation level is only nominally dependent on the temperature of the water At 20 C 68 F one liter of water can dissolve about 357 grams of salt a concentration of 26 3 percent by weight w w At 100 C 212 F the boiling temperature of pure water the amount of salt that can be dissolved in one liter of water increases to about 391 grams a concentration of 28 1 w w PropertiesWater NaCl phase diagramProperties of water NaCl mixtures NaCl wt Freezing point C Freezing point F Density g cm3 Refractive index at 589 nm Viscosity cP 0 0 32 0 99984 1 3330 1 0020 5 0 3 31 46 1 0018 1 3339 1 0111 0 59 30 94 1 0053 1 3347 1 022 1 19 29 86 1 0125 1 3365 1 0363 1 79 28 78 1 0196 1 3383 1 0524 2 41 27 66 1 0268 1 3400 1 0685 3 05 26 51 1 0340 1 3418 1 0856 3 7 25 34 1 0413 1 3435 1 1047 4 38 24 12 1 0486 1 3453 1 1248 5 08 22 86 1 0559 1 3470 1 1459 5 81 21 54 1 0633 1 3488 1 16810 6 56 20 19 1 0707 1 3505 1 19312 8 18 17 28 1 0857 1 3541 1 2514 9 94 14 11 1 1008 1 3576 1 31716 11 89 10 60 1 1162 1 3612 1 38818 14 04 6 73 1 1319 1 3648 1 46320 16 46 2 37 1 1478 1 3684 1 55723 3 21 1 5 98 1 17926 19 18 2 52 1 193 1 3795 1 676At some ambient temperature At some ambient temperature At some ambient temperature 20 C Eutectic mixture At 100 C 212 F 373 K saturated sodium chloride brine is about 28 salt by weight At 0 C 32 F 273 K brine can only hold about 26 salt At 20 C one liter of water can dissolve about 357 grams of salt a concentration of 26 3 The thermal conductivity of seawater 3 5 dissolved salt by weight is 0 6 W mK at 25 C 77 F The thermal conductivity decreases with increasing salinity and increases with increasing temperature The salt content can be determined with a salinometer Density r of brine at various concentrations and temperatures from 200 to 575 C 392 to 1 067 F can be approximated with a linear equation r lb ft3 a3 a2 T F displaystyle rho lb ft 3 a 3 a 2 cdot T F where the values of an are Weight a2 a35 0 043 72 6010 0 039 73 7215 0 035 74 8620 0 032 76 2125 0 030 77 85Electrolysis About four percent of hydrogen gas produced worldwide is created by electrolysis The majority of this hydrogen produced through electrolysis is a side product in the production of chlorine 2 NaCl aq 2 H2O l 2 NaOH aq H2 g Cl2 g See alsoBrackish water Brine Salinity SeawaterReferences Sodium Chloride MSDS Sigma Aldrich c 2004 Archived from the original on 2021 02 09 Lide D R ed 2005 CRC Handbook of Chemistry and Physics 86th ed Boca Raton Florida CRC Press pp 8 71 8 116 ISBN 0 8493 0486 5 CRC Handbook of Chemistry and Physics 63rd Edition 1982 1983 Solubility University of Wisconsin Fundamentals of Chemistry Archived from the original on 31 March 2016 Retrieved 6 November 2014 Thermophysical properties of seawater a review of existing correlations and data Paper published in April 2010 on web mit edu Retrieved 2021 03 11 https handbook ashrae org Handbooks F17 SI F17 Ch31 figures F31sf08 jpg Plots of thermal conductivity vs temperature for 0 5 25 w w NaCl water solutions Retrieved 2020 11 27 Thermal conductivity of seawater and its concentrates twt mpei ac ru Retrieved 2018 02 16 Dittman Gerald L February 16 1977 Calculation of Brine Properties Lawrence Livermore Laboratories Livermore CA doi 10 2172 7111583 External linksMedia related to Saline water at Wikimedia Commons
