NaCl solution

Figure A2.4.6. Mean activity coefFicient for NaCl solution at 25 °C as a function of the concentration full curve from ((A2A61 ) dashed curve from ((A2A63 ) dot-dashed curve from (A2.4.64). The crosses denote experimental data. From [2],...

Figure Bl.19.37. Nonual force versus tip-sample distance curves for a Si3N4 tip on a Si02 surface under 1 luM NaCl solution at pH 4 and pH 9. (Taken from [189], figure 2.)...

Thirty minutes after refluxing had stopped, a trace of copper(I) bromide was added to terminate the conversion. The reaction mixture was cautiously poured on to 500 g of finely crushed ice, then 200 ml of 4 N hydrochloric acid were added. After the remaining ice had melted the layers were separated and the aqueous layer was extracted three times with diethyl ether. The combined ethereal solutions were washed with saturated NaCl solution and dried over magnesium sulfate. The greater part of... 

After vigorous shaking the layers were separated and three extractions of the agueous layer with diethyl ether were carried out. The combined solutions were washed twice with saturated NaCl solution and then dried over magnesium sulfate. The greater part of the solvents was distilled off at normal pressure through a... 

Suspend 5 g of soluble starch in 50 mL of saturated NaCl solution, and stir slowly into 500 mL of boiling saturated NaCl solution. Cool and bottle. Free iodine produces a blue-black color. 

Compare the two methods in terms of the assumptions involved, the supple mentary information required, and the sensitivity to experimental error 11. The following values of n/c2 versus C2 were measuredf at 25°C in 0.15 NaCl solutions for bovine serum albumin ... 

Fig. 34. Solubility of chlorine ia water and aqueous HCl and NaCl. Solution concentrations are ia wt %.

The selectivityis so great that reversal of the reaction to restore the resin to the Na" form is not practical using NaCl solutions at any concentration. Regeneration with dilute acid, followed by conversion of the resulting form to the Na" form with dilute sodium hydroxide [1310-73-2] is the preferred alternative. 

When strong acid cation exchangers are used in the Na" form and strong base anion exchangers are used in the CL form, they are regenerated with a 10% sodium chloride [7647-14-5], NaCl, solution. Other concentrations may be used, perhaps with some adjustment in flow rate. 

Fig. 4. Mathcad simulations (Cp = 5000 mg/L) as a function of Reynolds number for a NaCl solution (a) concentration polarization (CP), and (b) (-...

Hydroxides. The hydrolysis of uranium has been recendy reviewed (154,165,166), yet as noted in these compilations, studies are ongoing to continue identifying all of the numerous solution species and soHd phases. The very hard uranium(IV) ion hydrolyzes even in fairly strong acid (- 0.1 Af) and the hydrolysis is compHcated by the precipitation of insoluble hydroxides or oxides. There is reasonably good experimental evidence for the formation of the initial hydrolysis product, U(OH) " however, there is no direct evidence for other hydrolysis products such as U(OH) " 2> U(OH)" 2> U(OH)4 (or UO2 2H20). There are substantial amounts of data, particulady from solubiUty experiments, which are consistent with the neutral species U(OH)4 (154,167). It is unknown whether this species is monomeric or polymeric. A new study under reducing conditions in NaCl solution confirms its importance and reports that it is monomeric (168). 8olubihty studies indicate that the anionic species U(OH) , if it exists, is only of minor importance (169). There is limited evidence for polymeric species such as Ug(OH) " 25 (1 4). 

Explosion Hazards. The electrolysis of aqueous solutions often lead to the formation of gaseous products at both the anode and cathode. Examples are hydrogen and chlorine from electrolysis of NaCl solutions and hydrogen and oxygen from electrolysis of water. The electrode reactions. 

There have been a number of cell designs tested for this reaction. Undivided cells using sodium bromide electrolyte have been tried (see, for example. Ref. 29). These have had electrode shapes for in-ceU propylene absorption into the electrolyte. The chief advantages of the electrochemical route to propylene oxide are elimination of the need for chlorine and lime, as well as avoidance of calcium chloride disposal (see Calcium compounds, calcium CHLORIDE Lime and limestone). An indirect electrochemical approach meeting these same objectives employs the chlorine produced at the anode of a membrane cell for preparing the propylene chlorohydrin external to the electrolysis system. The caustic made at the cathode is used to convert the chlorohydrin to propylene oxide, reforming a NaCl solution which is recycled. Attractive economics are claimed for this combined chlor-alkali electrolysis and propylene oxide manufacture (135). 

Concentration of Seawater by ED. In terms of membrane area, concentration of seawater is the second largest use. Warm seawater is concentrated by ED to 18 to 20% dissolved soHds using membranes with monovalent-ion-selective skins. The EDR process is not used. The osmotic pressure difference between about 19% NaCl solution and partially depleted seawater is about 20,000 kPa (200 atm) at 25°C, which is well beyond the range of reverse osmosis. Salt is produced from the brine by evaporation and crystallisa tion at seven plants in Japan and one each in South Korea, Taiwan, and Kuwait. A second plant is soon to be built in South Korea. None of the plants are justified on economic grounds compared to imported solar or mined salt. 

Fig. 2-22 Effect of stress intensity range dJC on crack propagation for a notched specimen of X60 steel in 3.5% NaCl solution at 0.1 Hz.

Fig. 5-4 Cell currents between a coated specimen (5 = 300 cm ) and uncoated steel electrode (5 =1.2 cm ) in NaCl solutions at 25°C. Left shot-peened steel sheet, 150 pva EP-tar. Right hot-dipped galvanized steel sheet, 150 jim EP-tar.

Fig. 6-3 J U) curves for pure zinc (machined surface) in 3.5 wt.% NaCl solution, free convection, not aerated.

Fig. 6-4 J U) curves for zinc anodes (material No. 2.2301) in 3.5 wt. % NaCl solution, aerated and stirred — at the start of the experiment -----after 90 h.

The first simulation studies of full double layers with molecular models of ions and solvent were performed by Philpott and coworkers [51,54,158] for the NaCl solution, using the fast multipole method for the calculation of Coulomb interactions. The authors studied the screening of a negative surface charge by free ions in several highly concentrated NaCl solutions. A combination of (9-3) LJ potential and image charges was used to describe the metal surface. 

FIG. 8 Density profiles p z) and running integrals n z) of the ion densities for cations (full lines) and anions (dashed lines) at three different surface charge densities in units of pC cm as indicated. Left NaCl solutions right CsF solutions. 

FIG. 10 Cation (full), anion (dashed), and oxygen (dotted) radial density distributions in nonpolar pores. Top NaCl solution bottom KCl solution. 

FIG. 8 Density profiles in a 4 m aqueous NaCl solution at 25°C. The semi-permeable membranes are at about 5 and 15 [25]. 

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