Subject sodium chloride, NaCl

A homogenized sample of cereals, vegetables, fruits or potatoes (10-20 g) is extracted with an organic solvent such as acetone and methanol. After filtration, the extract is concentrated to about 20 mL by rotary evaporation below 40 °C. The residue is transferred with 5% sodium chloride (NaCl) aqueous solution and partitioned twice with n-hexane. The n-hexane extracts are dried with anhydrous sodium sulfate and subjected to a Florisil column chromatographic cleanup procedure. The eluate from the Horisil column is concentrated to dryness and the residue is dissolved in an appropriate amount of acetone for analysis by GC/NPD. ... 

Although the structure of CsCl is quite different from that of NaCl, even CsCl can be transformed into the sodium chloride structure when heated to temperatures above 445 °C. Some of the other alkali halides that do not have the sodium chloride structure under ambient conditions are converted to that structure when subjected to high pressure. Many solid materials exhibit this type of polymorphism, which depends on the external conditions. Conversion of a material from one structure to another is known as a phase transition. 

When solid NaCl is heated to 801° C, it melts, and the ions are no longer fixed in a simple geometric pattern. They will move relative to each other, subject only to the constraint of electrostatic attraction and repulsion. Each Na, therefore, will be adjacent to as many Cl anions as possible, and each Cl will tend to be surrounded by Na cations. No longer would each ion be surrounded by precisely 6 ions of the opposite charge. This looser arrangement of ions in molten sodium chloride shows that the liquid state displays an increased disorder than the solid state, so it is of higher entropy. 

In most commercial processes, borax is obtained from lake brines, tincal and colemanite. The primary salt constituents of brine are sodium chloride, sodium sulfate, sodium carbonate and potassium chloride. The percent composition of borax as Na2B40 in brine is generally in the range 1.5 to 1.6%. Borax is separated from these salts by various physical and chemical processes. The brine solution (mixed with mother liquor) is subject to evaporation and crystahzation for the continuous removal of NaCl, Na2C03 and Na2S04, respectively. The hot liquor consists of concentrated solution of potassium salts and borate components of the brine. The insoluble solid particles are filtered out and the liquor is cooled rapidly in continuous vacuum crystallizers under controlled conditions of temperatures and concentrations to crystallize KCl. Cystallization of borax along with KCl from the concentrated liquor must not occur at this stage. KCl is separated from the hquor by filtration. Bicarbonate then is added to the liquor to prevent any formation of sodium... 

Hypertension is often treated with diuretics. Diuretics are drugs that promote the Joss of sodium from the body, though some diuretics can cause the loss of potassium, resulting in hypokalemia. The use of dietary supplements of K to correct this hypokalemia has been shown to be of benefit and to result in decreases in blood pressure. The best source of potassium is plant food, as is strikingly apparent from the data in Table IG.l however, the interest in nonfood supplements of potassium continues. One problem with potassium salts is that they taste bad and can produce nausea. Hence, there has been some interest in the manufacture of aesthetically acceptable forms of potassium salts. One form, a mixture of NaCl and KCl, is useful for those who feel compelled to add sodium chloride to their food. One study revealed that NaCI-KCl mixtures are accepted and their use can result in a reduction of sodium intake. The study, which involved normotensive subjects, did not lead to any consistent change in blood pressure (Mickeisen rt nI., 1977). 

A large number of chemical processes are carried out in solution and the application of chemical thermodynamics to solutions is an important part of the subject. Solutions can be gaseous, liquid, or solid. In this chapter we shall be concerned largely with solutions that are in the liquid state, for instance, mixtures of two liquids or the solution of a solid in a liquid. It is often convenient to refer to the substance which predominates in a solution as the solvent and to the minor constituent as the solute. In some solutions the components are miscible in all proportions. Thus ethanol and water will mix to form a homogeneous mixture whatever the relative quantities of ethanol and water. Other components will show limited mutual solubility. For example, only a limited amount of sodium chloride can be dissolved in water at any particular temperature. However much NaCl we add to a beaker of water the concentration of the salt will not exceed the value corresponding to a saturated solution. Some pairs of non-ionic substances, such as phenol and water, also show limited mutual solubility. 

Experimentally, three PMA based EAPs (from the same batch) were swollen in three different Group 1-Group 7 dilute electrolyte solutions 0.2 M LiBr, 0.2 M NaCl, and 0.2 M KCl. The EAPs were then subjected to a 50 V, 200 mA electric input for 3 min, with the positive electrode embedded in the EAP and the negative electrode external to the EAP. The EAPs swollen with potassium chloride produced the fastest and most pronounced contraction of 32%, followed by sodium chloride at 26% contraction, and followed by lithium bromide at 21% contraction (Fig. 4.13). 

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