Bases relative strength

A sufficient concentration of base B is necessary for the removal of a proton of the CH, group. In a first step, the equilibrium in Scheme 20 results, in which the monomeric anhydrobase Bi constitutes the conjugated base of the quaternary salt A,. As has been shown for other rings (24). the equilibrium depends upon the concentration of the different species and the relative strength of the bases B and Bj, and depends also upon the nature of X. 

Color Difference Evaluation. Shade evaluation is comparable in importance to relative strength evaluation for dyes. This is of interest to both dye manufacturer and dye user for purposes of quaUty control. Objective evaluation of color differences is desirable because of the well-known variabihty of observers. A considerable number of color difference formulas that intend to transform the visually nonuniform International Commission on Illumination (CIE) tristimulus color space into a visually uniform space have been proposed over the years. Although many of them have proven to be of considerable practical value (Hunter Lab formula, Friele-MacAdam-Chickering (FMC) formula, Adams-Nickerson formula, etc), none has been found to be satisfactorily accurate for small color difference evaluation. Correlation coefficients for the correlation between average visually determined color difference values and those based on measurement and calculation with a formula are typically of a magnitude of approximately 0.7 or below. In the interest of uniformity of international usage, the CIE has proposed two color difference formulas (CIELAB and CIELUV) one of which (CIELAB) is particularly suitable for appHcation on textiles (see Color). 

Procedures to compute acidities are essentially similar to those for the basicities discussed in the previous section. The acidities in the gas phase and in solution can be calculated as the free energy changes AG and AG" upon proton release of the isolated and solvated molecules, respectively. To discuss the relative strengths of acidity in the gas and aqueous solution phases, we only need the magnitude of —AG and — AG" for haloacetic acids relative to those for acetic acids. Thus the free energy calculations for acetic acid, haloacetic acids, and each conjugate base are carried out in the gas phase and in aqueous solution. 

Fiber Relative strength Specific gravity Normal moisture content (%) Maximum usable temperature ( F) Acid Base Organic solvent Other attribute... 

Table 2.3 Relative Strengths of Some Common Acids and Their Conjugate Bases...

I Table 13.4 Relative Strengths of Brensted-Lowry Acids and Bases ... 

To express the relative strengths of an acid and its conjugate base (a conjugate acid-base pair ), we consider the special case of the ammonia proton transfer equilibrium, reaction C, for which the basicity constant was given earlier (Kb = [NH4+l[OH ]/ NH3]). Now let s consider the proton transfer equilibrium of ammonia s conjugate acid, NH4+, in water ... 

Use K, values to predict the relative strengths of two acids or two bases (Example 10.5). 

Sections 10.9 and 10.10 discuss the relationship between molecular structure and the strengths of acids. The same ideas can be applied to bases, (a) Explain the relative strengths of the bases OH, NH,, and CH. (see Table 10.3). 

This is always the case for any two acids, and by measuring the positions of the equilibrium the relative strengths of acids and bases can be determined. Of course, if the two acids involved are close to each other in strength, a measurable reaction will occur from both sides, though the position of equilibrium will still be over to the... 

Based on the concept of mixed-framework lattices, we have reported a novel class of hybrid solids that were discovered via salt-inclusion synthesis [4—7]. These new compounds exhibit composite frameworks of covalent and ionic lattices made of transition-metal oxides and alkali and alkaline-earth metal halides, respectively [4]. It has been demonstrated that the covalent frameworks can be tailored by changing the size and concentration of the incorporated salt. The interaction at the interface of these two chemically dissimilar lattices varies depending upon the relative strength of covalent vs. ionic interaction of the corresponding components. In some cases, the weak interaction facilitates an easy... 

We express the relative strengths of weak acids and bases in terms of their dissociation constants. Shown... 

All applications of the lattice-gas model to liquid-liquid interfaces have been based upon a three-dimensional, typically simple cubic lattice. Each lattice site is occupied by one of a variety of particles. In the simplest case the system contains two kinds of solvent molecules, and the interactions are restricted to nearest neighbors. If we label the two types of solvents molecules S and Sj, the interaction is specified by a symmetrical 2x2 matrix w, where each element specifies the interaction between two neighboring molecules of type 5, and Sj. Whether the system separates into two phases or forms a homogeneous mixture, depends on the relative strength of the cross-interaction W]2 with respect to the self-inter-action terms w, and W22, which can be expressed through the combination ... 

Thus, the relative strengths of the acid (small pX (HA)) and of the base (large p/Ca(BH+)) decide whether the solution becomes acidic or alkaline. 

Table 3.1 Relative Strength of Selected Acids and their Conjugate Bases... 

Another type of classification of hydrogen bonds is based upon the relative strength of the interaction ... 

The hard-soft acid-base principle is not restricted to the usual types of acid-base reactions. It is a guiding principle that for all types of interactions species of similar electronic character interact best. We have already seen some applications (such as the relative strength of HF and HI) of this principle, which we will continue to call HSAB, but we now consider a number of other types of applications. 

The above equation has an equilibrium constant that is less than 1. What are the relative strengths of the acids and bases ... 

Thinking Critically Household ammonia is a mixture of ammonia and water. Based on the data you collected, is there more ammonia or more water in the mixture Use what you learned about the relative strengths of the attractive forces in ammonia and water to support your conclusion. 

The method of assessment of odour offensiveness was based on that of Sobel (19). 20 ml samples of slurry were tranferred to 60 ml black glass bottles as described by Williams (5). These were handed to panellists in their own offices or laboratories where they were already accustomed to the background odour and were least hindered by interruption. The panellists were shown a copy of Table I and asked to assign the odour offensiveness of each sample to a value between 0 and 5. They were specifically requested not to consider the samples relative strength compared with the other samples. 

If a salt consists of the cation of a weak base and the anion of a weak acid, both ions react with water. The solution is weakly acidic or weakly basic, depending on the relative strength of the ions that act as the acid or the base. You can determine which ion is stronger by comparing the values of and kj, associated with the cation and the anion, respectively. IfKa > kb, the solution is acidic. IfK, > K, the solution is basic. 

A solution of a certain salt is tested with litmus paper, and the litmus turns red. What does this tell you about the relative strengths of the acid and base from which the salt is derived ... 

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