Sodium fluoride common ions

They chose the TBDMS derivatives for reducing the polarity of hydroxyl groups of hydroxy fatty acid PNB esters because the TBDMS derivatives were resistant to hydrolysis, stable in common organic solvents, and changed the adsorption TLC and RP-HPLC retention of PNB hydroxy fatty acids more than smaller siloxy groups and because the TBDMS groups could easily be removed by fluoride ions (sodium fluoride or tetra-n-butyl ammonium fluoride) to free... 

Since hydrofluoric acid is a weak acid and only slightly dissociated, the major species in the solution are HF, Na+, F , and H20. The common ion in this solution is F, since it is produced by both hydrofluoric acid and sodium fluoride. What effect does the presence of the dissolved sodium fluoride have on the dissociation equilibrium of hydrofluoric acid ... 

The tin(II) halides are much less volatile than the corresponding tin(IV) compounds in fact, they are probably ionic, containing Sn2+ and X- ions. Tin(II) chloride in aqueous solution is commonly used as a reducing agent. Tin(II) fluoride (stannous fluoride) was for many years added to toothpaste to help prevent tooth decay. It has since been replaced by sodium fluoride. 

Most common ions (sodium, calcium, nitrate, phosphate, chlonne, bromide, and iodine) found in natural or wastewater are not really adsorbed onto activated carbons. An exception is fluoride that can be removed by activated carbon as well as by activated alumina. Table 24.6 gives some indications of the adsorption potential of some inorganic cations and anions onto carbonaceous porous material. 

Common ions can be determined at ppb levels, e.g. fluoride, chloride, nitrate, sulfate, sodium, ammonium, and potassium. This is especially important in environmental and industrial applications. Anion and cation analysis can be performed in many types of samples, e.g. groundwater samples, power plant waters, coastal and sea water samples, on air filters, solid waste samples, blood and food and digested rock samples. 

When a salt is added to a solution containing either the same cation or anion, there will be changes in the solubility because of what is commonly known as common-ion effect. This is so because the solubility of the salt added is affected by the common ions which are already present in the solution. Consider a solution of sodium fluoride (NaF). We are adding magnesium fluoride (MgF ) to this solution. Notice that there is a common ion in sodium fluoride and magnesium fluoride, namely fluoride. You will see that the solubility of magnesium fluoride will be less than expected. To be more precise, the solubility... 

Fluoride ion is commonly used in drinking water supplies and in toothpaste (in the form of sodium fluoride) to prevent tooth decay. The fluoride ions replace hydroxide ions in the enamel mineral hydroxyapatite [Cas(P04)30H, the same mineral as in bone], forming fluoroapatite [Ca5(P04)3Fj. Why does replacing the hydroxide ion with fluoride ion prevent tooth decay How does this relate to the properties of materials used in artificial fillings ... 

Halides Metal ion(s) + halogen ion Common salt (sodium chloride), a component of animal diets Fluorite (calcium fluoride), a lapidary material and flux... 

Nafion is a copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether. It has fixed anions, which are sulfonic acid sites, and consequently, by electroneutrality, the concentration of positive ions is fixed. Furthermore, the transference number of protons in this system is 1, which greatly simplifies the governing transport equations, as seen below. There can be different forms of Nafion in terms of the positive counterion (e.g., proton, sodium, etc.). Most models deal only with the proton or acid form of Nafion, which is the most common form used in polymer-electrolyte fuel cells due to its high proton conductivity. 

The same orthorhombic deformation of the perovskite structure, that Geller 111) reported of the ternary oxide GdFeOs, is according to Rudorff et al. 268, 270, 271), also present in the sodium compounds NaMeFs. The unequal sizes of the Na+- and fluoride-ions bring about a considerable distortion of their common close-packing. To describe the structure a... 

Table 5), and several are now being used, or are potentially useful, for measuring key ocean elements. The most common use of direct potentiometry (as compared with potentiometric titrations) is for measurement of pH (Culberson, 1981). Most other cation electrodes are subject to some degree of interference from other major ions. Electrodes for sodium, potassium, calcium, and magnesium have been used successfully. Copper, cadmium, and lead electrodes in seawater have been tested, with variable success. Anion-selective electrodes for chloride, bromide, fluoride, sulfate, sulfide, and silver ions have also been tested but have not yet found wide application. 

For example, chloride and fluoride ions, even in trace amounts (ppm), could cause the dissolution of aluminum metallization of complimentary metal oxide semiconductor (CMOS) devices. CMOS is likely to be the trend of VLSI technology and sodium chloride is a common contaminant. The protection of these devices from the effects of these mobile ions is an absolute requirement. The use of an ultrahigh purity encapsulant to encapsulate the passivated IC is the answer to some mobile ion contaminant problems. 

Calcium phosphate has become a common problem with the increase in treatment of municipal waste-water for reuse. Surface waters can also contain phosphate. Calcium phosphate compounds can contain hydroxyl, chloride, fluoride, aluminum, and/ or iron. Several calcium phosphate compounds have low solubility, as shown in Table 7.2. Solubility for calcium carbonate and barium sulfate are also shown by comparison. The potential for scaling RO membranes with the calcium phosphate compounds listed in Table 7.2 is high and will occur when the ion product exceeds the solubility constant. This can occur at orthophosphate concentrations as low as 0.5 ppm. Sodium softening or antisealants together with low pH help to control phosphate-based scaling. 

Ion chromatography (IC) was developed in the 1970s by Small et al. (1975). It is a powerful technique for the measurement of ionic species, such as fluoride, chloride, nitrite, nitrate, and sulphate and cations like lithium, sodium, ammonium, and potassium. It is very useful for analysis of anions for which there are no other rapid analytical methods, and it is also commonly used for organic species such as amino acids, amines, and proteins. The most commonly used detection method is conductivity,... 

The purpose of encapsulation is to protect electronic IC devices and prolong their reliability. Moisture, mobile ions, (eg., sodium, potassium, chloride, fluorides), UV-VIS and alpha particle radiation, and hostile environmental conditions are some of the possible causes of degradation or interaction which could negatively affect device performance or lifetime. Silicon dioxide, silicon nitride and silicon-oxy-nitride, commonly used as passivation layers have excellent moisture and mobile ion barrier properties and are, therefore, excellent encapsulants for devices. As for the... 

The main ions to be found in the oceans are sodium and chloride, i.e. seawater contains a relatively high concentration of common salt. Note that fluoride ions are not found in fresh water. 

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