Basic behaviour

H20(1) acts as an acid by donating a proton to the basic species and in doing so is converted into a base, OH (aq), the original base being converted into an acid. The acid-base behaviour is again essentially a proton transfer from one species to another. 

Simple bases such as NaOH and KOH act as sources of OH (aq) in aqueous solution. The OH (aq) ion is a base because it can accept a proton from a proton donor acid, H20(l), in aqueous solution. 

NHsCaq) also is a simple base. It acts as a base by accepting a proton from H20(l), thereby generating OH (aq). 

Bases which can accept one proton are termed monoacid, and those accepting two protons are diacidic. 

Some molecules contain both acidic and basic functional groups. The amino acids such as glycine, NH2CH2COOH, are common examples and they act as an acid or a base, depending on the circumstances. 

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Thus nitric acid behaves as a base in hydrogen fluoride. Hence increases of conductivity when substances dissolve in hydrogen fluoride may be due to acidic or basic behaviour. 

PNECs themselves are preferentially extrapolated from chronic toxicity data or, if no long-term data are available, acute toxicity data [51] they generally refer to algae, daphnia or fish toxicity. Sanderson et al., Stuer-Lauridsen et al., Boillot and Ferrari et al. [108-111] have reported PNECs for a large list of PhCs, and [49,112] recently proposed a model for the predicting PNEC of a substance, taking into consideration its acidic or basic behaviour in the environment. This procedure... 

Pure water containing no dissolved gases possesses equal concentrations of hydronium and hydroxide ions, so that pH = pOH = 7.0 at 298.15 K. This is defined as a neutral solution This allows a practical definition of acidic and basic behaviour. Any substance dissolved in water which produces a pH below 7 is termed an acid and any substance dissolved in water which produces a pH greater than 7 is called a base. 

Factors Influencing Acidic and Basic Behaviour in Aqueous Solutions... 

If the E—O bond breaks in a similar heterolytic manner, the compound exhibits basic behaviour ... 

The interaction between a and -it electrons of single and multiple bonds (or the -tt electrons in the aromatic ring) is usually interpreted (Baker, 1952) as a, -conjugation (hyperconjugation). In this process the hydrocarbons become stronger protolytes. For example, the acidic and basic behaviour of propene and toluene are more pronounced than the corresponding properties of ethylene and benzene. 

The exact value of H0 for pure 100% HF is uncertain as it appears to depend strongly on the presence of small amounts of impurities which are very difficult to remove the most important of these is water which exhibits weak basic behaviour. Thus the measured values of —H0 increase from 9-7 to 11-0 with decreasing impurity concentration, as indicated by the electrical conductivity (Hyman and Katz, 1965). The value of —11 0 was obtained with an acid that had a conductivity of 3 x 10-B ohm-1 cm-1 at 0°. Presumably, if the last traces of water and other impurities could be removed from HF, the value of — H0 would be greater than 11-0, perhaps as high as 11 -5. A few measurements have been made on solutions of sodium fluoride, which causes a marked decrease in — H0> and on a 0-02m solution of NbF6, which had H0 —12-5 (Hyman et al., 1961). 

Figure 2 By use of Eq (2), from an assumed pore diameter distribution density V(d) (full line) follows the corresponding CLD A [) (dashed line), Basic behaviour and maximum positions of K(rf) and A [) nearly agree.

Both reducing action and basic behaviour arc thus forms of electron donation. 

If the number of electrons decreases, an electrophilic attack or basic behaviour, electrophilic Fukui function may be related to the HOMO density,... 

No one knows for certain how or why programmed instruction works, but it is generally agreed that basic behavioural psychology is somehow involved. At least the originators of programmed instruction attributed its success to some basic tenets of behavioural psychology. 

The earliest work on this subject dealt with the basic behaviour of pyrrolines and tetrahydropyridines, and resulted in the development of a model according to which tertiary enamines would be more basic than their corresponding saturated amines. Later, Stamhuis and coworkers questioned this hypothesis by claiming that Af-isobute-nylpyrrolidine, AT-isobutenylpiperidine and iV-isobutenylmorpholine were less basic than their corresponding saturated amines, Table 2 gathers the most significant data on tertiary amines in this respect. 

The sorption of carboxylic acids on the acid form of zeolites has been studied previously [2,3,4]. It was claimed that the zeolite-OH sites shewed basic behaviour reacting with the acid to form acetate and water ... 

If we compare products calcinated at 500°C, SmP04 without treatment has a totally acidic behaviour while the sample treated at pH = 9 as a totally basic behaviour. The basic behaviour observed for SmP04 treated at pH = 9 indicates the presence of residual anions coming from the ammoniacal neutralization step. When calcinated at 700 °C, both products present comparable behaviour with an higher acidity for the phosphate not treated. At 700°C, we find the intrinsic acidic activity of samarium phosphate. 

This can be exemplihed by the acidic behaviour of propanoic acid, CH3CH2COOH, and the basic behaviour of the propanoate ion, CH3CH2COO. ... 

This can be exemplified by the basic behaviour of NH3(aq) and the acid behaviour of its conjugate acid NH4 (aq). 

The equivalence point for a weak acid will always occur at basic pH values, e.g. pH = 8.14 for the case quoted. This reflects the basic behaviour of the salt formed, in contrast to the neutral behaviour of NaCl in the strong acid/strong base titration. Furthermore, the change in pH around the equivalence point is much less dramatic, again reflecting the fact that the salt formed is involved in an acid/base equiUbriiun. The buffer region shows a smooth increase in pH with addition of strong base. 

In Section 3.5, it was stated that aliphatic aminoacids and aminophenols showed strongly contrasting behaviour when studied over a range of pH. Both show acidic and basic behaviour and, for both, the titration curves show two p T values and two end-points. 

Sulfuric acid is a highly acidic solvent and most other acids are neutral or behave as bases in it we have already noted the basic behaviour of HNO3. Initial proton transfer (equation 8.8) leads to the formation of the protonated acid [H2N03]+, and in such cases, the resulting species often eliminates water (equation 8.9). Protonation of H2O follows (equation 8.10). 

Fig. 5. Schematic representation of the acidic and basic behaviour of the oxygen-containing sur cc groups and delocalized Ji-electrons of the basal plane...

I actors inlluenciiii acidic and basic behaviour in aqueous solutions were discussed. 

According to the nature of the substituent group anodically introduced into the aromatic hydrocarbon, various deviations from the basic behaviour can occur. For example oxidation of anthracene in acetonitrile containing a trace of water leads to the reaction scheme ... 

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