Basic properties hydrolysis

A number of trends connected with ionic radii are noticeable across the series. In keeping with Fajans rules, salts become somewhat less ionic as the Ln " radius decreases reduced ionic character in the hydroxide implies a reduction in basic properties and, at the end of the series, Yb(OH)3 and Lu(OH)3, though undoubtedly mainly basic, can with difficulty be made to dissolve in hot cone NaOH. Paralleling this change, the [Ln(H20)j ] + ions are subject to an increasing tendency to hydrolyse, and hydrolysis can only be prevented by use of increasingly acidic solutions. 

Urea possesses negligible basic properties (Kb = 1.5 x 10 l4), is soluble in water and its hydrolysis rate can be easily controlled. It hydrolyses rapidly at 90-100 °C, and hydrolysis can be quickly terminated at a desired pH by cooling the reaction mixture to room temperature. The use of a hydrolytic reagent alone does not result in the formation of a compact precipitate the physical character of the precipitate will be very much affected by the presence of certain anions. Thus in the precipitation of aluminium by the urea process, a dense precipitate is obtained in the presence of succinate, sulphate, formate, oxalate, and benzoate ions, but not in the presence of chloride, chlorate, perchlorate, nitrate, sulphate, chromate, and acetate ions. The preferred anion for the precipitation of aluminium is succinate. It would appear that the main function of the suitable anion is the formation of a basic salt which seems responsible for the production of a compact precipitate. The pH of the initial solution must be appropriately adjusted. 

Possible modes of regulation of filament assembly may be anticipated from the basic properties of actin. We have shown that the tightly bound divalent metal ion (Ca or Mg ) interacts with the P- and y-phosphates of ATP bound to actin, and that the Me-ATP bidentate chelate is bound to G-actin in the A configuration. The nature of the bound metal ion affects the conformation of actin, the binding kinetics of ATP and ADP, and the rate of ATP hydrolysis. 

Nitroguanidine has weakly basic properties and this accounts for its ability to form salts with concentrated acids, e.g. it forms a sulphate with concentrated sulphuric acid. Nitroguanidine is hydrolysed on heating with concentrated sulphuric acid evolving nitrous oxide and carbon dioxide, the former probably derived from hydrolysis of nitramine and the latter from hydrolysis of cyanamide. The latter also yields ammonia on decomposition. 

Hydrolysis Acidic and Basic Properties of Salts/ Chemical Demonstrations, A Handbook for Teachers of Chemistry, Vol. 3 (The University of Wisconsin Press, Madison, 1989) pp. 103-108. 

The actinide ions in 5+ and 6+ oxidation states are prone to severe hydrolysis as compared to lower oxidation states in view of their high ionic potentials. Consequently, these oxidation states exist as the actinyl ions MOt and MO + even under acidic conditions, which can further hydrolyze under high pH conditions. The oxygen atoms of these ions do not possess any basic property and thus do not interact with protons. The tetravalent ions do not exist as the oxy-cations and can be readily hydrolyzed at low to moderate pH solutions. The degree of hydrolysis for actinide ions decreases in the order M4 > MOT > M3 > MOt, which is similar to their complex formation properties (4). In general, the hydrolysis of the actinides ions can be represented as follows ... 

This article surveys the research work on the synthesis and modification reactions of poly(ethyleneimine) as well as its applications to metal complexation processes. Poly-(ethyleneimine), one of the most simple heterochain polymers exists in the form of two different chemical structures one of them is branched, which is a commercially available and the other one linear which is synthesized by cationic polymerization of oxazoline monomers and subsequent hydrolysis of polyf(/V acylimino)cthylcne]. The most salient feature of poly(ethyleneimine) is the simultaneous presence of primary, secondary, and tertiary amino groups in the polymer chain which explains its basic properties and gives access to various modification reactions. A great number of synthetic routes to branched and linear poly(ethyleneimine)s and polymer-analogous reactions are described. In addition, the complexation of polyfethyleneimine) and its derivatives with metal ions is investigated. Homogeneous and heterogeneous metal separation and enrichment processes are reviewed. 

The reader is already familiar with the weakly basic properties of ammonia. The commercial preparations of this base, both from the elements and from hydrolysis of calcium cyanamide, have already been noted. For preparation of small quantities of ammonia in the laboratory, an ammonium salt, either dry or in solution, may be heated with base. 

The relative rates of reaction for the hydrolysis and condensation dictate the structure and properties of an alkoxide gel. These reaction rates are schematically described in Figure 8.18 [43] for the example of a silicon ethoxide. In acidic solutions, hydrolysis is achieved by a bimolecular displacement mechanism that substitutes a hydronium ion (H" ) for an alkyl [44]. Under these conditions the hydroljreis is rapid compared to the condensation of the hydrolyzed monomers and promotes the development of larger and more linear molecules, as is described in Figure 8.19. Under basic conditions, hydrolysis occurs by nucleophilic substitution of hydrojgrl ions (OH ) for alkyl groups [45]. Here the condensation is rapid relative to hydrolysis, promoting the precipitation of three-dimensional colloidal particles as shown in Figure 8.17(b) and 8.19. 

Trivalent molybdenum is found in a few simple compounds. The black hydroxide, Mo(OH)3, dissolves in acids -with salt formation, yielding reddish-purple solutions which darken in colour. Upon evaporation crystalline salts are not obtained, but when the solution is taken to dryness a greyish-black residue remains, which can be redissolved in water to a dark grey solution. This may be accounted for by the readiness with which the salts undergo hydrolysis, with formation of the black hydroxide, possibly in the eoUoidal form. The similarity of molybdenum to chromium is seen in the series of complex For indications of basic properties in the trioxide, see p. 137. 

The unstable, colourless, liquid diphosphine (m.p. —99°, b.p. 51.7°) is a minor by-product of the hydrolysis of phosphides (CagPg) which give mainly phosphine it is separated from the latter by freezing. Unhke hydrazine it is without basic properties. But like hydrazine it is readily oxidised and is a strong reducing agent it has the same structure. There the similarity ends because its lone pairs are quite ineffective, so that it is insoluble in water and without trace of basic character. It is photo- and heat-sensitive giving phosphine and phosphorus ... 

Fats, when heated with a solution of NaOH or KOH are hydrolyzed. After the hydrolysis, glycerine and long chained carboxylic acids salts are left, this mixture is soap and the process is called saponification. Soaps are basic salts which are formed by weak fatty acids and strong bases. For this reason, soap solutions show basic properties. Saponification is the reverse process of esterification. 

The hydrated Na ion has no acidic or basic properties. The acetate ion CH3COO , however, is the conjugate base of the weak acid CH3COOH and therefore has an affinity for ions. The hydrolysis reaction is given by... 

As seen from the content of this Part of the book, the formation of basic products of addition of oxide ions to the normal neutral anions is the rule rather than the exception, and is connected with the higher basic properties of O as compared with OH, which is the strongest of the possible bases in aqueous medium. Hydrolysis is the most obvious reason it is well-known that the constant of the following equilibrium... 

Piperidine, C5H10NH, is prepared by the electrolytic reduction of pyridine. It is one of the products of the hydrolysis of piperine the essential principle of pepper. Piperidine boils at 106° and possesses a pepper-like odor it has well characterized basic properties. It has recently been used as an accelerator in the vulcanization of rubber. 

One of the basic properties of siloxenes is their general insolubility in organic solvents, a fact that strongly impedes physical and structural characterization. As a result, the question arose as to whether structurally better defined siloxene-like polymers with improved solubility can be assembled in a stepwise manner starting from appropriate molecular precursors, and whether the properties of siloxene, such as the intense photoluminescence, can be matched. We thus attempted to rebuild the proposed structure of Kautsky-siloxene by the controlled hydrolysis of cyclic or linear oligosilanes bearing hydrolytically labile substituents followed by the thermal condensation to polymeric siloxanes. The general route is outlined in Scheme 16.1. 

Correct choice (B) describes this process. Choice (D) is an incorrect variation. It is not the dirt in the hard water that is precipitating with the soap, it is previously dissolved ions. Choice (C) gives incorrect assumptions about the both the acidic nature of solutions required by soap and the basic property of hard water. Choice (A) uses a somewhat familiar term, hydrolysis, but it is used incorrectly in this case. Hydrolysis for the stearate ion describes the interaction of the ion with water to produce the conjugate acid and release hydroxide ions, not a factor in forming the observed precipitate. ... 

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