Solubility strong bases

Pyrrohdine [123-75-1] (tetrahydropyrrole) (19) is a water-soluble strong base with the usual properties of a secondary amine. An important synthesis of pyrrohdines is the reaction of reduced furans with excess amine or ammonia over an alumina catalyst in the vapor phase at 400°C. However, if labde substituents are present on the tetrahydrofurans, pyrroles may form (30). 

Discussion. The hydroxides of sodium, potassium, and barium are generally employed for the preparation of solutions of standard alkalis they are water-soluble strong bases. Solutions made from aqueous ammonia are undesirable, because they tend to lose ammonia, especially if the concentration exceeds 0.5M moreover, it is a weak base, and difficulties arise in titrations with weak acids (compare Section 10.15). Sodium hydroxide is most commonly used because of its cheapness. None of these solid hydroxides can be obtained pure, so that a standard solution cannot be prepared by dissolving a known weight in a definite volume of water. Both sodium hydroxide and potassium hydroxide are extremely hygroscopic a certain amount of alkali carbonate and water are always present. Exact results cannot be obtained in the presence of carbonate with some indicators, and it is therefore necessary to discuss methods for the preparation of carbonate-free alkali solutions. For many purposes sodium hydroxide (which contains 1-2 per cent of sodium carbonate) is sufficiently pure. 

KOH is a water-soluble strong base, not an acid. As a strong base it will react with an acid. Iron(II) hydroxide, Fe(OH)2, is insoluble and will precipitate. 

The chlorine atoms in these compounds are unusually labile, especially in the case of the cis isomer, which in aqueous and alcoholic solution yields an immediate precipitate with silver nitrate, while the trans isomer reacts more slowly. This lability also causes interconversion to occur readily, as during recrystallization from water or often in metatheses. The two isomers can readily be distinguished by treatment with silver(I) oxide.2 The cis compound reacts immediately to give the soluble strong base [Pt (C2-H5)2S 2(OH)2], while the trans compound slowly decomposes to black platinum(II) oxide and diethyl sulfide, the solution remaining neutral. 

The thallium(I) ion Tl+ behaves in certain respects as an alkali metal ion (although in others more like Ag+). Its ionic radius (1.54 A) is comparable to that of Rb+, although it is more polarizable. Thus TlOH is a water-soluble, strong base, which absorbs C02 from the air to form the... 

The most common soluble strong bases are the ionic hydroxides of the alkali metals, such as NaOH, KOH, and the ionic hydroxides heavier alkaline earth metals, such as Sr(OH)2. These compounds completely dissociate into ions in aqueous solution. Thus, a solution labeled 0.30 M NaOH consists of 0.30 MNa ([Pg.665]

The term alkaline is essentially a synonym for basic, it refers to any solution containing appreciable OH (aq) or a substance that can form such a solution. Thus, alkalis are soluble strong bases, such as NaOH and KOH. Alkali metal means any metal of the group Na, K, Li, Rb, and Cs. In general, the oxides of metallic elements are basic, and the oxides of nonmetallic elements are acidic. 

A wide variety of solution condensation systems were devised and tested including one and two liquid combinations and salt-containing systems. Only the system using the stannane dissolved in DMSO and dextran with sodium hydroxide in water yielded the desired modified cellulosic product (Table 1). Other results indicate that the presence of a strong base is conducive to effecting the modification of the cellulose. The DMSO systems had the NaOH present only as a largely undissolved solid. Further studies should consider the use of DMSO, DMF, etc. soluble strong bases such as triethylenediamine. 

In part (a), the net ionic equation is H (aq) + OH (aq) —> H20(l), as is always the case when the neutralization reaction involves a soluble strong acid and a soluble strong base. In part (b), the base was not soluble thus, the net ionic equation includes a solid. 

Triton B Trade name for benzyltrimethyl-ammonium hydroxide usually as a 40% solution in methanol. A strong base, soluble in many solvents used as a catalyst. See phase transfer chemistry. 

The hydroxides M OH are all soluble in water, in which they behave as strong bases, for example... 

Iron(II) hydroxide [18624-44-7], Fe(OH)2, is prepared by precipitation of an iron(II) salt solution by strong base in the absence of air. It occurs as pale green, hexagonal crystals or a white amorphous powder. It is practically insoluble in water, fairly soluble in ammonium salt solutions, and soluble in acids and in concentrated NaOH solution. It is slowly oxidized by air. Conversion to Fe203 atH20 is eventually complete. 

Chemical methods to determine the crystalline content in silica have been reviewed (6). These are based on the solubility of amorphous silica in a variety of solvents, acids or bases, with respect to relatively inert crystalline silica, and include differences in reactivity in high temperature fusions with strong bases. These methods ate qualitative, however, and fail to satisfy regulatory requirements to determine crystallinity at 0.1% concentration in bulk materials. 

The characteristics of soluble sihcates relevant to various uses include the pH behavior of solutions, the rate of water loss from films, and dried film strength. The pH values of sihcate solutions are a function of composition and concentration. These solutions are alkaline, being composed of a salt of a strong base and a weak acid. The solutions exhibit up to twice the buffering action of other alkaline chemicals, eg, phosphate. An approximately linear empirical relationship exists between the modulus of sodium sihcate and the maximum solution pH for ratios of 2.0 to 4.0. 

CeUulose is soluble only in unusual and complex solvent systems. The subject has been reviewed (84—87). Commercially, dissolving pulps, which have lower molecular weights, are used along with strong alkaU and derivatization. CeUulose subjected to high temperature and pressure during the steam explosion process can be dissolved in strong base (88). 

Cesium hydroxide monohydrate [35103-79-8] CsOH H2O, mol wt 167.93, theoretical cesium content 79.14 wt %, is a colorless, hygroscopic, crystalline powder, having a melting point of 205—208°C and a specific gravity of 3500 kg/m. It is highly soluble, 8.6 kg/L of water at 15°C similar to the anhydrous hydroxide, it is an extremely strong base. 

Choline is a strong base (pif = 5.06for0.0065-0.0403 Afsolutions ) (3). It crystallizes with difficulty and is usually known as a colorless deHquescent sympy hquid, which absorbs carbon dioxide from the atmosphere. Choline is very soluble in water and in absolute alcohol but insoluble in ether (4). It is stable in dilute solutions but in concentrated solutions tends to decompose at 100°C, giving ethylene glycol, poly(ethylene glycol), and trimetbylamine (5). 

The alkaloids are strong bases, which turn red litmus blue, and are very slightly soluble m water. They form soluble salts and double salts wdth platmic and auric chlorides. The principal general reagents for the alkaloids are ... 

Compounds of Tl have many similarities to those of the alkali metals TIOH is very soluble and is a strong base TI2CO3 is also soluble and resembles the corresponding Na and K compounds Tl forms colourless, well-crystallized salts of many oxoacids, and these tend to be anhydrous like those of the similarly sized Rb and Cs Tl salts of weak acids have a basic reaction in aqueous solution as a result of hydrolysis Tl forms polysulfldes (e.g. TI2S3) and polyiodides, etc. In other respects Tl resembles the more highly polarizing ion Ag+, e.g. in the colour and insolubility of its chromate, sulfide, arsenate and halides (except F), though it does not form ammine complexes in aqueous solution and its azide is not explosive. 

Let us apply these ideas to the third-row elements. On the left side of the table we have the metallic reducing agents sodium and magnesium, which we already know have small affinity for electrons, since they have low ionization energies and are readily oxidized. It is not surprising, then, that the hydroxides of these elements, NaOH and Mg(OH)z, are solid ionic compounds made up of hydroxide ions and metal ions. Sodium hydroxide is very soluble in water and its solutions are alkaline due to the presence of the OH- ion. Sodium hydroxide is a strong base. Magnesium hydroxide, Mg(OH)2, is not very soluble in water, but it does dissolve in acid solutions because of the reaction... 

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