Acid-base reactions reaction units

In an acid-base reaction, the reaction unit is the proton. For an acid, the number of reaction units is given by the number of protons that can be donated to the base and for a base, the number of reaction units is the number of protons that the base can accept from the acid. In the reaction between H3PO4 and NaOH, for example, the weak acid H3PO4 can donate all three of its protons to NaOH, whereas the strong base NaOH can accept one proton. Thus, we write... 

Proton transfers between oxygen and nitrogen acids and bases are usually extremely fast. In the thermodynamically favored direction, they are generally diffusion controlled. In fact, a normal acid is defined as one whose proton-transfer reactions are completely diffusion controlled, except when the conjugate acid of the base to which the proton is transferred has a pA value very close (differs by g2 pA units) to that of the acid. The normal acid-base reaction mechanism consists of three steps ... 

Hypotheses about metabolism are abundant for the hypothetical life in acidic aerosols. In strong acid, the C=C bond is reactive as a base and can support a metabolism as an analog of the C=0 unit. This type of chemical reactivity is exemplified in some terran biochemistry. For example, acid-based reactions of the C=C unit have been used by plants as they synthesize fragrant molecules.16... 

No example has so far been reported of a shuttling process controlled by electron transfer chemical reactions. There are, however, very interesting examples of shuttling processes controlled by acid/base reactions. One case is that of the previously discussed compound 13 " (see Figure 14), in which the shuttling of the macrocycle component can be controlled not only electrochemically, but also by protonation/ deprotonation of the benzidine unit [43]. 

In considering the mass law expression, for example, for an acid-base reaction HA = A -I- H, the activities of the solutes are defined in reference to the standard state of a 1-molar concentration. These activities are, in principle, ratios to A" o, HA o, and and are entered in molar units. The... 

Write balanced formula unit, total ionic, and net ionic equations for an acid-base reaction that will produce the salt, barium chloride. 

Arrhenius and Bronsted-Lowry acid-base neutralization reactions all have one thing in common. They involve the reaction of an acid with a base to form a salt that contains the cation characteristic of the base and the anion characteristic of the acid. Water is also usually formed. This is indicated in the formula unit equation. The general form of the net ionic equation, however, is different for different acid-base reactions. The net ionic equations depend on the solubility and extent of ionization or dissociation of each reactant and product. 

Donor-Acceptor Principle. Particle aggregates, but also the atomic units of matter themselves can interact or react with each other and can thereby develop attraction and repulsion forces, and can transfer particles or energy. These particles or energies are transferred from one partner to the other [15]. The transmitted particles or energies can be (a) protons, (b) electrons, (c) ligands. In this respect, one can see school-made misconceptions with regard to (a) acid-base reactions (Chap. 7), (b) redox reactions (Chap. 8), and (c) complex reactions (Chap. 9). 

Not all acid-base reactions occur in a 1 1 combining ratio (as hydrochloric acid and sodium hydroxide in the previous example). Acid-base reactions with other than 1 1 combining ratios occur between what are termed polyprotic substances. Polyprotic substances donate (as acids) or accept (as bases) more than one proton per formula unit. 

Normality is another unit of concentration that is sometimes used, especially when dealing with acids and bases. The use of normality focuses mainly on the H and OH" available in an acid-base reaction. Before we discuss normality, however, we need to define some terms. One equivalent of an acid is the amount of that acid that can furnish 1 mol ofH ions. Similarly, one equivalent of a base is defined as the amount of that base that can furnish 1 mol ofOH ions. The equivalent weight of an acid or a base is the mass in grams of 1 equivalent (equiv) of that acid or base. 

Although the amino and carboxyl groups in the peptide linkage are nonfunctional in acid-base reactions, all proteins contain a number of free amino and carboxyl groups, either as terminal units or in the side chain of amino acid residues. Like amino acids, proteins are therefore amphoteric. They exhibit characteristic isoelectric points and have buffering properties. 

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