Hydrolysis salts

When the salt of a strong acid and a strong base is dissolved in water it produces a pH of ca 7.0. When salts of a weak acid and a strong base or of a strong acid and a weak base are dissolved in water they will produce respectively alkaline and acidic solutions. 

When sodium acetate is dissolved in water the acetate ion behaves as a base removing protons from solution. For a weak electrolyte in water KbxKa = Kw. If a 0.1 M solution of sodium acetate in water is considered  

Regarding the change in the concentration of water as not affecting the equilibrium and regarding the [CHjCOO ] as being relatively unchanged by hydrolysis. 

Calculate the pH of a 0.1 M solution of NH4CI. Here salt hydrolysis increases [H ] and the equilibrium in this case is  

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The amines are comparatively weak bases, so that a certain amount of free amine will be produced by salt hydrolysis unless an excess of acid is present. The reaction mixture must be kept very cold during the process (which is exothermic in character), otherwise the diazonium salt may be partially converted into the corresponding hydroxy compound ... 

Precipitated K—salt crystals are carefully filtrated and washed so as to separate them from the mother solution. Drying of filtrated K-salt is also a very delicate and important process that must be performed under conditions that avoid hydrolysis of the material. Potassium heptafluorotantalate is sensitive to water, basic compounds and alcohols, especially at elevated temperatures. The main product of K-salt hydrolysis is Marignac s salt. For a long time it was believed that the composition of Marignac s salt is K/Ta Fg. However, X-ray crystal structure analysis and precise chemical analysis of the... 

The phenomenon of salt hydrolysis may be regarded as a simple application of the general Bronsted-Lowry equation... 

Salicylaldehyde oxime 475 Salt bridge 531, 582 prepn. of, 582 Salt effect 25 Salt hydrolysis 40... 

After bleaching, the a-sulfonated ester has to be neutralized with sodium hydroxide or some other aqueous base to obtain the salt. Hydrolysis of the ester groups is avoided if the temperature does not exceed 45 °C and the pH is between 7.5 and 9. Neutralization is thus performed in a continuous process to ensure pH control and effective heat removal [33]. The concentration of the NaOH solution has to be calculated so that a slurry is obtained that has a low viscosity so as to facilitate further processing. For example, neutralization can produce a 40% aqueous slurry of sodium palm kernel methyl ester a-sulfonate or a 25% aqueous slurry of sodium tallow methyl ester a-sulfonate [33],... 

Aqueous electrolytes proposed in the literature for cathodic electrodeposition of lead selenide are generally composed of dissolved selenous anhydride and a lead salt, such as nitrate or acetate. Polycrystalline PbSe films have been prepared by conventional electrosynthesis from ordinary acidic solutions of this kind on polycrystalline Pt, Au, Ti, and Sn02/glass electrodes. The main problem with these applications was the PbSe dendritic growth. Better controlled deposition has been achieved by using EDTA in order to prevent PbSeOs precipitation, and also acetic acid to prevent lead salt hydrolysis. 

A. Alkaline Hydrolysis. -The low kinetic isotope effect observed in the protonation of carbanions formed in phosphonium salt hydrolysis leads to the idea that there is little breaking of the phosphorus-carbon bond and correspondingly little transfer of a proton to the incipient carbanion in the transition state (87) of the rate-determining step. ... 

A formal definition of salt hydrolysis can follow from the description outlined above. Salt hydrolysis may be defined as a reaction in which the anion or the cation of a salt reacts with the solvent water to produce acidity or alkalinity. Evidently, it is the nature of the anion or the cation constituting the salt which will determine whether the solution produced as a result of hydrolysis will be acidic or alkaline. If the matter is examined from these points of view, the following three different cases can arise. 

Description of hydrolysis of salt Hydrolysis constant (KH) Degree of hydrolysis (h)... 

Except for the last, these reactions are used in titrimetric neutralization analysis.) Reactions (II) to (IV) can also proceed in the opposite direction. This will be demonstrated on the well-known example of salt hydrolysis. 

Merocyanine Dye Method for Acid Analysis. Resist photochemistry can often be monitored by the changes in ultraviolet absorption spectra associated with a bleaching of the sensitizer absorbance. In the case of resist systems with triphenylsulfonium salts, no change in the film absorption is observed on irradiation. In order to determine the amount of acid produced, a direct method for acid analysis was required. A highly sensitive method was desirable since the amount of acid produced is approximately 10 6 mmol for a 1 micrometer thick film on a 2 inch wafer. Furthermore a nonaqueous technique is preferred in order to avoid hydrolysis of the hexafiuoroantimonate salt. Hydrolysis gives hydrogen fluoride (14) which makes accurate acid determination more difficult. 

Nitriles of the aromatic acids may be obtained fiom the sulfonic acids or from diazonium salts. Hydrolysis of the nitrile produces the carboxylic acid ... 

The first oxidative studies on N-acylglycosylamines were conducted on a preparative scale by Niemann and Hays.65 The N-acetyl-D-glucopyranosylamine (69) obtained by acetylation of D-glucopyranos-ylamine with ketene (or by acetylation of this amine, followed by ammonolysis) was oxidized by way of the dialdehyde 70 to the acid 71, isolated as the strontium salt. Hydrolysis of 71 led to D(+)-glyceric acid (72), thus showing the pyranose structure of 69. 

Related ammonium salts derived from amines, such as [CH3NH3]C1, [(CH3)2NH2]C1, and [(CH3)3NH]C1, also give acidic solutions because they too have cations with at least one dissociable proton. The pH of a solution that contains an acidic cation can be calculated by the standard procedure outlined in Figure 15.7. For a 0.10 M NH4C1 solution, the pH is 5.12. Although the reaction of a cation or anion of a salt with water to produce H30+ or OH - ions is sometimes called a salt hydrolysis reaction, there is no fundamental difference between a salt hydrolysis reaction and any other Bronsted-Lowry acid-base reaction. 

Imidate salts hydrolysis, 118-144 syn and anti, 120 isomerization, 142 B-lactam, 142 Iminium salts, 211-221 Imino-ethers, 147 lodolactonization, 169 Ionic state of tetrahedral intermediates, 65, 105-106, 119 Ionophore A-23187, 13 Isochromane-3-one, 70 Isocyanate, 300 Isonitrile, 296... 

Here again, loss of Y = H would result in rearomatization and formation of 12, but in the case of Y = Me, this cannot occur. However, assistance by the amine nitrogen lone pair can aid the rearomatization process, producing the copper-bound phenol product and an imininm salt. Hydrolysis during the workup procedure could release the 2-meth-ylphenol product and result in a retro-Mannich reaction to give the observed secondary amine (PY2) and formaldehyde. A small amount (<10%) of N—Me—PY2 is often observed as a byproduct and its yield is at the expense of the PY2 and formaldehyde thus, it appears to be derived from direct reduction of the intermediate iminium salt [167],... 

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