Solubility rules for

TABLE 11.46 General Solubility Rules for Inorganic Compounds ... 

General solubility rules for the commonly encountered ions ... 

TABLE 2.1 Solubility Rules for Ionic Compounds in Water... 

Water. It should come as no surprise that ordinary water can be an excellent solvent for many samples. Due to its extremely polar nature, water will dissolve most substances of likewise polar or ionic nature. Obviously, then, when samples are composed solely of ionic salts or polar substances, water would be an excellent choice. An example might be the analysis of a commercial iodized table salt for sodium iodide content. A list of solubility rules for ionic compounds in water can be found in Table 2.1. 

General solubility rules for water as a solvent must be stated in two parts, one emphasizing the negative ions of the salts, and the other emphasizing the positive ions, as follows. 

The solubility rules for common salts. The solubility of gases in liquids—Henry s law. The partition of a solute between two solvents. 

Table 2 Solubility Rules for Some Common Ionic Compounds...

We can assume that the precipitate that formed in our test tube must be one (or both) of the possible products from our word equation. In order to identify which of the products formed, we would need to find out which of the products is insoluble in water and would therefore precipitate out. Our most handy reference tables for this type of problem will contain the solubility rules for ionic compounds, shown here, and/or a solubility table (see Figure 6-3a). 

TABLE 4.2 Solubility Rules for Common Ionic Compounds in Water at 25°C... 

SOME SOLUBILITY RULES FOR INORGANIC SALTS IN WATER Compound Solubility ... 

Table 9.6 lists the solubility rules for ionic compounds in water. 

For most analyses, standard solutions are aqueous solutions containing several percent of a mineral acid such as HCl or nitric acid. When mixing different elements in acids, it is important to remember basic chemistry and solubility rules for inorganic compounds. The elements must be compatible with each other and soluble in the acid used so that no precipitation reactions occur. Such reactions would change the solution concentration of the elements involved in the reaction and make the standard useless. Combinations to be avoided are silver and HCl, barium and sulfuric acid, and similar... 

The exceptions to our generalization about solubility are most easily given in the form of solubility rules for simple compounds containing anions that are important in minerals ... 

Therefore, you must know solubility rules for solids and gases, and you must know common weak acids and bases. You should have memorized the strong acids and bases and then can assume that other acids and bases are weak. 

Suppose you are trying to help your friend understand the general solubility rules for ionic substances in water. Explain in general terms to your friend what the solubility rules mean, and give an example of how the rules could be applied in determining the identity of the precipitate in a reaction between solutions of two ionic compounds. 

Summarize the simple solubility rules for ionic compounds. How do we use these rules in determining the identity of the solid formed in a precipitation reaction Give examples including balanced complete and net ionic equations. 

Calculate AG° for the dissolution of both sodium chloride and silver chloride using data from Appendix E. Explain how the values you obtain relate to the solubility rules for these substances. 

In Section 3.3, we introduced the term solubility to measure how much of a solute a particular solvent can dissolve. This idea is frequently translated into the solubility rules for ionic substances, which we introduced in Section 3.3 (page 91). Those rules classify both silver bromide and silver cyanide as insoluble. But in Example Problem 12.3, we implied that there was a measurable difference in solubility between those two compounds. So we need to refine our notion of what it means for a compound to be insoluble. We will be more accurate if we refer to salts such as silver bromide and silver cyanide as sparingly soluble. Given enough time and a constantly refreshing solvent (in other words, not equilibrium conditions), even the most insoluble salt will dissolve. The dissolution of mountains by rainfall represents such a process, albeit one that requires hundreds of thousands of years. So how can we specify just how soluble an insoluble compound is ... 

To help understand the solubility rules for ionic compounds, think about the magnitudes of the charges on the cation and anion. The higher the charges are, the more strongly the anion and cation attract one another and the less soluble the salt is likely to be. For example, almost all salts composed of 1 + cations and 1 - anions are soluble (Ag salts are a notable exception). Almost all salts composed of 2 +/2 - and 3 +/3 - ion pairs are insoluble (or only slightly soluble). 

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