Solutions of Acids, Bases, and Salts

Acids are substances that produce H+ ion in water solution and bases are substances that produce OH ion. Salts are substances that are composed of ions and that contain a cation other than H+ and an anion other than OH . Salts can be produced by the reaction between H+ ion from an acid and OH ion from a base, a neutralization reaction. As a specific example, consider the reaction of H+ from a solution of sulfuric acid, H2SO4, with OH from a solution of calcium hydroxide  

In addition to water, which is always the product of a neutralization reaction, the other product is calcium sulfate, CaS04. This compound is a salt composed of Ca + ions and SO ions held together by ionic bonds. A salt, consisting of a cation other than H+ and an anion other than the OH ion, is the other product in addition to water produced when an acid and a base react. Some 

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The US Bureau of Mines found the chemical and galvanic corrosion behaviour of both the TZM and Mo-30W alloy to be generally equal or superior to that of unalloyed molybdenum in many aqueous solutions of acids, bases and salts. Notable exceptions occurred in 6-1 % nitric acid where both alloys corroded appreciably faster than molybdenum. In mercuric chloride solutions the TZM alloy was susceptible to a type of crevice corrosion which was not due to differential aeration. The alloys were usually not adversely affected by contact with dissimilar metals in galvanic couple experiments, but the dissimilar metals sometimes corroded galvanically. Both alloys were resistant to synthetic sea water spray at 60°C. 

The rest of this chapter is a variation on a theme introduced in Chapter 9 the use of equilibrium constants to calculate the equilibrium composition of solutions of acids, bases, and salts. We shall see how to predict the pH of solutions of weak acids and bases and how to calculate the extent of deprotonation of a weak acid and the extent of protonation of a weak base. We shall also see how to calculate the pH of a solution of a salt in which the cation or anion of the salt may itself be a weak acid or base. 

Aqueous solutions of acids, bases, and salts are the ionic conductors used most widely and studied most thoroughly. The importance of other types of ionic conductors has increased in recent times, but aqueous solutions are still preeminent. Their significance goes far beyond electrochemistry as such they can be found in practically all spheres of human activity. They are of exceptional importance in the... 

Since in the interconversion of electrical and chemical energies, electrical energy flows to or from the system in which chemical changes lake place, it is essential that the system be. in large part, conducting or consist of electrical conductors. These are of two general types—electronic and electrolytic—though some materials exhibit both types of conduction. Metals are the most common electronic conductors. Typical electrolytic conductors are molten salts and solutions of acids, bases, and salts. 

The theory of electrolytic dissociation, AVhereas the osmotic pressure and the other colligative properties of aqueous solutions of substances, such as cane sugar, obey van t Hoff s laws, marked deviations are met with in aqueous solutions of acids, bases, and salts, even at great dilutions. The osmotic pressure and lowering of the freezing point for these solutions are still found to be approximately proportional to the molecular concentration, but are considerably greater than the theoretical values. To allow for this van t Hoff introduced a new term into his osmotic pressure equation, writing for such solutions... 

E7.7 Electrical Conductivity of Solutions of Acids, Bases and Salts... 

In the experiment described below two cells made of zinc, copper, and sulphuric acid are set up and joined in series, that is, the copper of one cell is joined to the zinc of the next. In this way it is possible to obtain a current that will decompose solutions of acids, bases, and salts. 

STANDARD SOLUTIONS OF ACIDS, BASES, AND SALTS (continued)... 

The van t Hoff theory was found to be inapplicable to solutions of acids, bases and salts, as they yielded osmotic pressures greater than predicted on the basis of their molar concentrations. In these cases the PV = RT equation had to be modified to PV = iRT, where i was a factor which varied from one solute to another and increased with dilution. Raoult showed that solutions of these same solutes had abnormally large freezing-point depressions. 

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