Sodium chloride aqueous solutions, relative humidity

Group IV. Ca, Sr, and Ba This is a difficult separation. The metals are present as chlorides. The solvent used is pyridine containing 20 per cent (v/v) water and 1 per cent (w/v) potassium thiocyanate. The elution is allowed to proceed for 5-6 hours in an atmosphere saturated with respect to pyridine and also with a relative humidity of between 65 and 80 per cent the latter is attained by the use of a saturated aqueous solution of ammonium nitrate or chloride. The solvent front moves about 20 cm. The strip is dried, and then sprayed with a saturated alcoholic solution of alizarin to identify Ca, and with 0 5 per cent (w/v) aqueous sodium rhodizonate (freshly prepared) to reveal Ba and Sr. The RF values are Ca, 0-95 Sr, 0-75 Ba, 0-15 (see Fig. VI.5c). 

One can control an equilibrium amount of water uptake by the membranes and also the size of the ionic clusters by changing relative humidity of the membranes or by immersing the membranes in aqueous solutions of sodium chloride with different concentrations (11.). Figure 13 shows change of SAXS profiles upon immersing the sodium-sulfonated (a) and -carboxylated membranes having 1100 E.W. (b) into the aqueous sodium-chloride solutions with various concentrations. 

Atmospheric aerosols at high relative humidities are aqueous solutions of species such as ammonium, nitrate, sulfate, chloride, and sodium. Cloud droplets, rain, and so on are also aqueous solutions of a variety of chemical compounds. 

CALCIUM CHLORIDE. CaCU bH.O. In laboratory tests, solid calcium chloride caused moderate attack (- 6 mpy) of alloys 3003, 5154, and 6061 under conditions of 100% relative humidity at ambient temperature. Other laboratory tests show that aqueous solutions (up to 45%) caused mild attack at ambient temperature with pitting in evidence. The action of calcium chloride can be inhibited by the addition of sodium dichromate. Inhibited calcium chloride refrigeration brines have been commonly handled in aluminum alloy equipment. Alloy 356.0 valves have been used for handling calcium chloride solutions. See also Ref (1) p. 128, (2) p. 129, (3) pp. 23, 73. 240, (7) p. 47. 

Alternate Immersion in 3.5% NoCl. Exposure to 3.5% sodium chloride or to substitute ocean water (ASTM D 1141) by alternate immosion (ASTM G 44) (see Table 1) is a widely used procedure for testing smooth specimens of aluminum alloys. Aeration of the specimens, achieved by the alternate immersion, enhances the corrosion potential (Ref 26) and produces more rapid SCC of most aluminum alloys than continuous immersion. The ASTM G 44 standard practice consists of a 1 h cycle that includes a 10 min soak in the aqueous solution followed by a SO min period out of solution in air at 27 °C (80 °F) and 45% relative humidity, during which time the specimens are air dried, lliis 1 h cycle is repeated continuously for the total number of days recommended for the particular alloy being tested. IVpically, aluminum alloys are exposed from 10 to 90 days, depending on the resistance of the alloy to corrosion by salt water. This test ntethod is widely used for testing most types of aluminum alloys with all types of smooth specimens. 

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