Nitrate ions bromide

We have seen in Experiment 8 that silver chloride has low solubility in water. This is also true for silver bromide and silver iodide. In fact, these low solubilities provide a sensitive test for the presence of chloride ions, bromide ions, and iodide ions in aqueous solutions. If silver nitrate... 

Theory. The anion exchange resin, originally in the chloride form, is converted into the nitrate form by washing with sodium nitrate solution. A concentrated solution of the chloride and bromide mixture is introduced at the top of the column. The halide ions exchange rapidly with the nitrate ions in the resin, forming a band at the top of the column. Chloride ion is more rapidly eluted from this band than bromide ion by sodium nitrate solution, so that a separation is possible. The progress of elution of the halides is followed by titrating fractions of the effluents with standard silver nitrate solution. 

Ogura and Hanya [62-65] investigated the components of the ultraviolet absorption in an attempt to devise a useful method for oceanic dissolved organic carbon measurements. They concluded that while the method might have limited application in coastal waters, most of the absorption in oceanic waters was due to the inorganic components, principally nitrate and bromide ions. 

Methscopolamine Methscopolamine, 7-(3-hydroxy-l-oxo-2-phenylpropoxy)-9, 9-dimethyl-3-oxa-9-azoniticyclo[3.2.1.0. " ]nonane nitrate (14.1.7), is synthesized by reacting scopolamine (14.1.6) with methylbromide and sometimes with a subsequent replacement of the bromide ion with a nitrate ion by using silver nitrate [9,10]. 

None of these things happened when we tried this reaction. What did happen —and it took some puzzling to figure it out—was that it reacted with a nitrate ion as the solvent to give two chromate ions plus nitryl ion, and the nitryl ion made nitryl bromide which decomposes to bromine and N02. Incidentally, we found that... 

Besides using the bioactive agent to detect the ion of interest, another approach can include monitoring an ion by its inhibitory effect upon enzymatic activity. For example, horseradish peroxidase (HRP) can be immobilised onto one gate of a REFET [107] allowing the presence of cyanide ion to be measured at concentrations of 10 3-10 7 M. The approach used here is to monitor the inhibition of the enzymatic HRP effect, by the cyanide ion, on ascorbic acid. Even lower levels (10 10 M) of detection can be obtained using a polyphenol oxidase/clay composite immobilised on carbon, with no interference from chloride, nitrate or bromide [108]. 

Chromates, vanadates, and cerium salts give colour reactions with the reagent and should therefore be absent. Iron salts give a yellow colour with hydrogen peroxide, but this is eliminated by the addition of syrupy phosphoric acid. Fluorides bleach the colour (stable [TiF6]2 ions are formed), and large amounts of nitrates, chlorides, bromides, and acetates as well as coloured ions... 

Let us look at some of the evidence for this mechanism. If a carbonium ion is the intermediate, we might expect it to react with almost any negative ion or basic molecule that we care to provide. For example, the carbonium ion formed in the reaction between ethylene and bromine should be able to react not only with bromide ion but also— if these are present—with chloride ion, iodide ion, nitrate ion, or water. 

Chemically bonded aminopropyl phases have also been successfully employed for the separation of inorganic ions. Leuenberger et al. [19] described the separation of nitrate and bromide in foodstuffs on such a phase using a phosphate buffer solution as the eluent. These alternative techniques are also described in Chapter 5. However, it is presently very difficult to comment on their potential for universal applicability, since they have mainly been used for the analysis of UV-absorbing species. 

The retention model developed by Eon and Guiochon [7,8] to describe the adsorption effects at both gas-liquid and liquid-solid interfaces, which was later modified by Mdckel et al. [6] to account for the retention at chemically bonded reversed-phase materials in HPLC, is not applicable to ion chromatography. But if the dependence of the capacity factors of various inorganic anions on the column temperature is studied, certain parallels with HPLC are observed. The linear dependences shown in Fig. 3-2 are obtained for the ions bromide and nitrate when the In k values are plotted versus the reciprocal temperature (van t Hoff plot). However, in the case of fluoride, chloride, nitrite, orthophosphate, and sulfate, the k values were found to be constant within experimental error limits in the temperature range investigated. Upon linear regression of the values in Table 3-1, the following relations are derived for bromide and nitrate ... 

Electrodes suitable for the potentiometric determination of surfactants are either specially designed liquid or solid membrane electrodes or ion-selective electrodes that in addition to being selective to a particular ion, also quantitatively respond to surfactants. For example, a nitrate ion-selective electrode responds to anionic surfactants, a calcium ion-selective electrode is sensitive to quaternary ammonium salts, and a barium ion-selective electrode can be used for assaying polyethoxylates [43], In some cases it is possible for one to perform potentiometric determination of a counter-ion, e.g. one can titrate alkylpyridinium chloride or bromide salts with silver nitrate solution using silver wire as an indicator electrode [38]. 

Most selenium measurements are complicated by the presence of other elements in the sample. In some cases selenium can be separated from interferences by distillation as the bromide, by high pressure liquid chromatography, or by solvent extraction (1, 12, 13). The hydride generation technique provides good separation of selenium from interferences in the atomic absorption technique that has been developed. However, separation from arsenic and mercury is not accomplished, and these elements and the nitrate ion have been found to interfere (14,15). However, the effect of these species on the measurement is not significant for the method developed by the Project. 

Besides the effect of the position and identity of the substituent in the pyridinium groups on the transport number between anions, the water contents of the membranes differ according to the nature of pyridine derivatives reacted with the membranes. Figure 5.38 shows the relationship between the transport numbers of various anions relative to chloride ions and water contents of the membranes reacted with ethyl pyridines.103 The permeation of nitrate and bromide ions decreases and that of fluoride ions increases with increasing membrane water content when ethyl pyridines are reacted with the membranes. However, /cis°4 is independent of water content. This might be due to the low mobility of sulfate... 

Table 5.8 Change in transport numbers of fluoride, bromide and nitrate ions relative to chloride ions by photoirradiationa...

Figure 5.49 shows the transport numbers of various anions (sulfate, fluoride, bromide and nitrate) relative to chloride ions for a membrane having an azobenzene moiety (M-2 membrane) before and after UV irradiation when 1 1 mixed salt solutions (concentration of sodium ions 0.150 N) were electrodialyzed. The transport numbers of all anions increase upon UV irradiation due to the increase in water content, which is based on the increase in dipole moment of the azobenzene moiety of the membrane by UV irradiation, and the increase in pore size of the membrane due to isomerization from the trans to the cis form.135 In particular the permeation of halide ions, (fluoride and bromide) increases remarkably. Fluoride ions permeate more selectively through the membrane than chloride ions.135 The increase in permeation of multi-atomic anions (sulfate and nitrate) is not large, which might be because they suffer steric hindrance. After amination of the M-2 membrane with trimethylamine (M-3 membrane), the permeation of sulfate and fluoride ions decreases and that of bromide and nitrate ions increases compared with the M-l membrane without UV irradiation. This is due to introduction of a bulky, hydrophobic group, the azobenzene moiety, into the membrane. However, the transport numbers of the measured anions (sulfate,... 

An attempt to determine the stability constants of the nickel bromo complexes was complicated by the slow formation of bromine from oxidation of bromide by the nitrate ion. However, the results indicated that the bromo and chloro complexes of nickel(II) have similar stability. 

These ions with their opposite charges attract each other in the same way as do the simple ions in binary ionic compounds. However, the individual polyatomic ions are held together by covalent bonds, with all of the atoms behaving as a unit. For example, in the ammonium ion, NH +, there are four N—H covalent bonds. Likewise, the nitrate ion, N03, contains three covalent N—O bonds. Thus, although ammonium nitrate is an ionic compound because it contains the NH " and N03 ions, it also contains covalent bonds in the individual polyatomic ions. When ammonium nitrate is dissolved in water, it behaves as a strong electrolyte like the binary ionic compounds sodium chloride and potassium bromide. As we saw in Chapter 8, this occurs because when an ionic solid dissolves, the ions are freed to move independently and can conduct an electric current. 

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