Sodium chloride hardness

HA. See Hydroquinone monomethyl ether Halite. See Sodium chloride Hard paraffin. See Paraffin HAS. See Hydroxylamine sulfate HBCD. See Hexabromocyclododecane HBD. See Tributyltin oxide HBPA. See Bisphenol A, hydrogenated HBVE adipate. See Bis (4-vinyl oxy butyl) adipate HBVE hexamethylene diurethane. See Bis 4-vinyl oxy butyl) hexanediyl-biscarbamate... 

Phthalide. In a 1 litre bolt-head flask stir 90 g. of a high quality zinc powder to a thick paste with a solution of 0 5 g. of crystallised copper sulphate in 20 ml. of water (this serves to activate the zinc), and then add 165 ml. of 20 per cent, sodium hydroxide solution. Cool the flask in an ice bath to 5°, stir the contents mechanically, and add 73-5 g. of phthalimide in small portions at such a rate that the temperature does not rise above 8° (about 30 minutes are required for the addition). Continue the stirring for half an hour, dilute with 200 ml. of water, warm on a water bath imtil the evolution of ammonia ceases (about 3 hours), and concentrate to a volume of about 200 ml. by distillation vmder reduced pressure (tig. 11,37, 1). Filter, and render the flltrate acid to Congo red paper with concentrated hydrochloric acid (about 75 ml. are required). Much of the phthalide separates as an oil, but, in order to complete the lactonisation of the hydroxymethylbenzoic acid, boil for an hour transfer while hot to a beaker. The oil solidifles on cooling to a hard red-brown cake. Leave overnight in an ice chest or refrigerator, and than filter at the pump. The crude phthalide contains much sodium chloride. RecrystaUise it in 10 g. portions from 750 ml. of water use the mother liquor from the first crop for the recrystaUisation of the subsequent portion. Filter each portion while hot, cool in ice below 5°, filter and wash with small quantities of ice-cold water. Dry in the air upon filter paper. The yield of phthalide (transparent plates), m.p. 72-73°, is 47 g. 

Brine Preparation. Rock salt and solar salt (see Chemicals frombrine) can be used for preparing sodium chloride solution for electrolysis. These salts contain Ca, Mg, and other impurities that must be removed prior to electrolysis. Otherwise these impurities are deposited on electrodes and increase the energy requirements. The raw brine can be treated by addition of sodium carbonate and hydroxide to reduce calcium and magnesium levels to below 10 ppm. If further reduction in hardness is required, an ion-exchange resin can be used. A typical brine specification for the Huron chlorate ceU design is given in Table 6. 

Cation exchange of hardness salts, using potassium chloride (KC1) as a regenerant, rather than sodium chloride. KC1 is considerably more expensive than ordinary salt (NaCl), but it is promoted as being medically and environmentally superior. 

Phosphate need not be used in boilers where hardness can be eliminated from the FW at all times. Its use is not recommended for boilers that may exhibit severe hideout (see the section on coordinated phosphate treatment). In these circumstances, sodium hydroxide is the preferred alkalizing agent and should be dosed to a maximum of 1.5x the sodium chloride content. 

The average composition of seawater is shown in Table 1-3. Seawater muds have sodium chloride concentrations above 10,000 ppm. Most of the hardness in seawater is caused by magnesium. 

From the results of Part A, and using words like soft, ductile, malleable, brittle, hard, or pliable, how would you describe sodium chloride ... 

Based on the ionic radii, nine of the alkali halides should not have the sodium chloride structure. However, only three, CsCl, CsBr, and Csl, do not have the sodium chloride structure. This means that the hard sphere approach to ionic arrangement is inadequate. It should be mentioned that it does predict the correct arrangement of ions in the majority of cases. It is a guide, not an infallible rule. One of the factors that is not included is related to the fact that the electron clouds of ions have some ability to be deformed. This electronic polarizability leads to additional forces of the types that were discussed in the previous chapter. Distorting the electron cloud of an anion leads to part of its electron density being drawn toward the cations surrounding it. In essence, there is some sharing of electron density as a result. Thus the bond has become partially covalent. 

The formation of sodium chloride is a strong driving force in this reaction. The hard-soft interaction principle (see Chapter 9) is convenient in this case because of the favorable interaction of Na+ with Cl A Other examples of this type of reaction are the following ... 

The particular amphoteric resin that is employed in the BDH process has a high affinity for calcium and magnesium chloride in concentrated sodium chloride brines. In dilute solutions the selectivity is lost, so that regeneration can be effected with a simple water wash. The process was found to be effective over a wide range of hardness and brine concentrations. 

Also the effect of impurities in a crystal on the Vickers hardness was analysed. In Figure 4 are shown the force dependency curves of the Vickers hardnesses of a pure sodium chloride crystal and a sodium chloride crystal grown in a solution with an impurity of 10 % urea. The hardness of the pure sodium chloride crystal is up to 25 % higher than the hardness of the impure crystal. 

Figure 4. Force-dependency of the Vickers hardness for pure sodium chloride and sodium chloride crystals grown in a solution with an impurity of 10 % urea...

Close-packed spheres occupy 74.04% of a total volume, hence the hard-sphere radius of I" in these 2 1 salts in 2.03 A. Correction for the electrostatic attraction alone would give a monovalent iodide radius of about 2.24, an opposite repulsion-correction for the different co-ordination number would reduce this to about 2.10 A for the monovalent sodium-chloride type (see Appendix). Such values are consistent with our earlier estimates, but incompatible with the electron-density minimum value (4) of 1.94 A. 

There are two types of caverns used for storing liquids. Hard rock (mined) caverns are constructed by mining rock formations such as shale, granite, limestone, and many other types of rock. Solution-mined caverns are constructed by dissolution processes, i.e., solution mining or leaching a mineral deposit, most often salt (sodium chloride). The salt deposit may take the form of a massive salt dome or thinner layers of bedded salt that are stratified between layers of rock. Hard rock and solution-mined caverns have been constructed in the United States and many other parts of the world. 

Different surfactants are usually characterised by the solubility behaviour of their hydrophilic and hydrophobic molecule fraction in polar solvents, expressed by the HLB-value (hydrophilic-lipophilic-balance) of the surfactant. The HLB-value of a specific surfactant is often listed by the producer or can be easily calculated from listed increments [67]. If the water in a microemulsion contains electrolytes, the solubility of the surfactant in the water changes. It can be increased or decreased, depending on the kind of electrolyte [68,69]. The effect of electrolytes is explained by the HSAB principle (hard-soft-acid-base). For example, salts of hard acids and hard bases reduce the solubility of the surfactant in water. The solubility is increased by salts of soft acids and hard bases or by salts of hard acids and soft bases. Correspondingly, the solubility of the surfactant in water is increased by sodium alkyl sulfonates and decreased by sodium chloride or sodium sulfate. In the meantime, the physical interactions of the surfactant molecules and other components in microemulsions is well understood and the HSAB-principle was verified. The salts in water mainly influence the curvature of the surfactant film in a microemulsion. The curvature of the surfactant film can be expressed, analogous to the HLB-value, by the packing parameter Sp. The packing parameter is the ratio between the hydrophilic and lipophilic surfactant molecule part [70] ... 

Recently, diet low in NaCl has been indispensable for health conscious people in modem civilized countries. At present, an average Japanese takes about 12 g of sodium chloride a day. Patients who need a low sodium chloride diet are suggested to reduce intake to 3 g a day. It is not difficult to reduce sodium chloride intake to 10 g a day under attentive health care. However, it is hard to reduce sodium chloride intake to less than 8 g a day as long as our daily life depends on natural foods. 

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