Brine

Brine is a solution of salt (usually sodium chloride) in water. In different contexts, brine may refer to salt solutions ranging from about 3.5% (a typical concentration of seawater, or the lower end of solutions used for brining foods) up to about 26% (a typical saturated solution, depending on temperature). Other levels of concentration are called in different names:
It is held that 0 °F (−17.78 °C) was initially set as the zero point in the Fahrenheit temperature scale, as it was the coldest temperature that Daniel G. Fahrenheit could reliably reproduce by freezing brine.gwydir.demon.co.uk
==Properties==
 Properties of - mixtures
NaCl, wt%	Freezing point (°C)	Density (g/cm3)	Refractive index at 589 nm	Viscosity (cP )
0 	0 	0.99984 	1.333 	1.002
0.5 	−0.3 	1.0018 	1.3339 	1.011
1 	−0.59 	1.0053 	1.3347 	1.02
2 	−1.19 	1.0125 	1.3365 	1.036
3 	−1.79 	1.0196 	1.3383 	1.052
4 	−2.41 	1.0268 	1.34 	1.068
5 	−3.05 	1.034 	1.3418 	1.085
6 	−3.7 	1.0413 	1.3435 	1.104
7 	−4.38 	1.0486 	1.3453 	1.124
8 	−5.08 	1.0559 	1.347 	1.145
9 	−5.81 	1.0633 	1.3488 	1.168
10 	−6.56 	1.0707 	1.3505 	1.193
12 	−8.18 	1.0857 	1.3541 	1.25
14 	−9.94 	1.1008 	1.3576 	1.317
16 	−11.89 	1.1162 	1.3612 	1.388
18 	−14.04 	1.1319 	1.3648 	1.463
20 	−16.46 	1.1478 	1.3684 	1.557
22 	−19.18 	1.164 	1.3721 	1.676
At 100 °C (373.15 K, 212 °F), saturated sodium chloride brine is about 28% salt by weight i.e. 39.12 g salt dissolves in 100 mL of water at 100 °C. At 0 °C (273.15 K, 32 °F), brine can only hold about 26% salt.CRC Handbook of Chemistry and Physics, 63rd Edition 1982-1983.
The thermal conductivity of seawater (3.5% dissolved salt by weight) is 0.6 W/mK at 25 °C.web.mit.edu The thermal conductivity decreases with increasing salinity and increases with increasing temperature; these graphs and online calculations plot thermal conductivity for varying salinity and temperature:twt.mpei.ac.ru
Density of brine at various concentrations and temperatures can be approximated with a linear equation:
Density (lb/ft3)= a3 - (a2*Temperature (F)) where the values of an are:
Weight %	a2 	a3
5 	.043	72.60
10 	.039	73.72
15 	.035	74.86
20 	.032	76.21
25 	.030	77.85
==Electrolysis of brine==
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 Na(aq) + H2(g) + Cl2(g)
==Usages==
===Refrigerating fluid===
Brine is a common fluid used in large refrigeration installations for the transport of thermal energy from place to place. It is used because the addition of salt to water lowers the freezing temperature of the solution and the heat transport efficiency can be greatly enhanced for the comparatively low cost of the material. The lowest freezing point obtainable for NaCl brine is −21.1 °C (−6.0 °F) at 23.3wt% NaCl.webserver.dmt.upm.es This is called the eutectic point.
===De-icing===
In colder temperatures, brine can be used to de-ice or reduce freezing temperatures on roads.Iowa Department of Transportation Certain forms of road salt, such as magnesium chloride, have been banned in some jurisdictions because of their increased impact to road infrastructure such as concrete bridges, as well as roadside vegetation.Performance and Impacts of Current Deicing and Anti-icing Products: User Perspective versus Experimental Data, by Fay, Volkening, Gallaway and Shi, Montana State University.
===Culinary===
In cooking, brine is used for food brining and salting.
==Hydrology==
In hydrology, brine is a form of salt water, namely, water with relatively high concentration of salt (usually sodium chloride). 
==See also==
* Saline water
* Brackish water
 
==References==
Category:Air Pollution
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