Soluble ionic hydroxide

Bases accept (or take) hydrogen ions. In water, the strongest possible base is the hydroxide ion, OH-. A strong base ionizes essentially 100% to produce the OH- ion, so a strong base is a soluble ionic hydroxide. Like all soluble ionic compounds, ionic hydroxides are strong electrolytes and dissociate completely... 

Any soluble, ionic hydroxide may be used. We know that barium hydroxide (to... 

Adding lime to soil makes the soil less acidic and more favorable for growing many types of plants. Because Ca(OH)2 is only slightly water soluble, it provides a longer-lasting source of base than provided by more soluble ionic hydroxides. 

Why are soluble ionic hydroxides always strong bases ... 

From a practical standpoint, we can identify bases through their bitter taste, slippery feel, and effect on the colors of acid-base indicators (Fig. 5-9). The Arrhenius definition of a base is a substance that produces hydroxide ions (OFf ) in aqueous solution. Consider a soluble ionic hydroxide, such as NaOFl. In the solid state, this compound consists of Na" " and OFf ions. When the solid dissolves in water, the ions dissociate. 

The strong acids listed in Table 16.3 are molecular compounds whereas the strong bases are soluble ionic compounds called hydroxides. Molecular compounds ionize in water Neutral HA molecules produce H3O and A ions by reacting with water (equation 16.9). On the other hand, soluble ionic hydroxides dissociate in water Positive and negative ions (for example, Na and OH ), which are already present in the solid structure, enter the solution as free ions (Fig. 14-6). 

A1P04, used in cements and as an antacid (c) iron(II) hydroxide, Fe(OH)2 (d) Select two soluble ionic compounds that, when mixed in solution, form each of the insoluble compounds in parts (a), (b), and (c). Identify the spectator ions. 

As pure compounds, acids are covalent. When placed in water, they react with the water to form ions it is said that they ionize. If they react 100% with the water, they are said to be strong acids. The seven common strong acids are listed in Table 7-3. All the rest are weak that is, the rest ionize only a few percent, and largely stay in their covalent forms. Both strong and weak acids react 100% with metal hydroxides. All soluble metal hydroxides are ionic in water. 

The most familiar examples of strong bases are alkali metal hydroxides, MOH, such as NaOH (caustic soda) and KOH (caustic potash). These compounds are water-soluble ionic solids that exist in aqueous solution as alkali metal cations (M + ) and OH- anions ... 

Not many ionic hydroxides are soluble except for the hydroxides of the Group 1A and Group 2A metals (except for magnesium—Mg(OH)2 is insoluble). So, the commonly encountered strong bases include the following ... 

Ra Solubility of hydroxides in water ns2 Ionic nature of halides Group-13 Elements Increasing Decreasing Exceptions Trends Trends... 

Bases provide hydroxide ions to aqueons solntion. Soluble metal hydroxides, including those of the alkali metals and barium, are examples. The soluble metal hydroxides are ionic even when they are pure solids they remain ionic in water. When they are dissolved in water, the hydroxide ions are totally separated from the metal ions. A soluble metal hydroxide is a strong base. A weak base is not 100% ionized. Ammonia, the most common weak base, reacts with water to a small extent to provide hydroxide ions ... 

What does a net ionic equation actnally tell us As an example, the net ionic equation of Example 9.3 indicates that any strong acid in water reacts with any soluble strong hydroxide to yield water as a product. The ions that do not react are not of immediate concern. However, no aqueous solution contains only ions or only OH ions. The net ionic equation does not state that these ions occur without ions of the opposite charge, only that the identities of the oppositely charged ions are not important because they do not react (Figure 9.4). 

In aqueous solutions of ionic compounds, the ions act independently of each other. Soluble ionic compounds are written as their separate ions. We must be familiar with the solubility rules presented in Chapter 8 and recognize that the following types of compounds are strong electrolytes strong acids in solution, soluble metallic hydroxides, and salts. (Salts, which can be formed as the products of reactions of acids with bases, include all ionic compounds except strong acids and bases and metalhc oxides and hydroxides.) Compounds must be both ionic and soluble to be written in the form of their separate ions. (Section 9.1)... 

Other metals form ionic hydroxides, but these are so sparingly soluble in water that they cannot produce strongly basic solutions. They are called insoluble bases or sometimes sparingly soluble bases. Typical examples include Cu(OH)2, Zn(OH)2, Fe(OH)2, and Fe(OH)3. 

In Section 4-2 we examined some reactions of strong acids with strong bases to form soluble salts. Let us illustrate one additional example. Perchloric acid, HCIO4, reacts with sodium hydroxide to produce sodium perchlorate, NaC104, a soluble ionic salt. 

A substance may dissolve with or without reaction with the solvent. For example, when metallic sodium reacts with water, there is the evolution of bubbles of hydrogen and a great deal of heat. A chemical change occurs in which H2 and soluble ionic sodium hydroxide, NaOH, are produced. 

The simplest kind of base is a water-soluble ionic compoimd, such as sodium hydroxide, that contains the hydroxide ion as the negative ion. When NaOH dissolves in water, for example, it dissociates into aqueous sodium ions and hydroxide ions, as shown below. 

Because NaOH is a water-soluble ionic compound, it separates into sodium ions, Na" ", and hydroxide ions, OH , when it dissolves in water. Thus, at the instant that the two solutions are mixed, the solution contains water molecules, hydronium ions, H30", chloride ions, Cl , sodium ions, Na, and hydroxide ions, OH . When the hydronium ions collide with the hydroxide ions, they react to form water. If an equivalent amount of acid and base are added together, the H3O and the OH will be completely reacted. n O+ aq) + OH-(aq) 2H20(/)... 

Because K2CO3 is a water-soluble ionic compound, it separates into potassium ions, K, and carbonate ions, C03 , when it dissolves in water. The carbonate ions are weakly basic, so they react with water in a reversible reaction to form hydrogen carbonate, HCO3 and hydroxide, OH . 

Strong and weak acids have one or more H atoms as part of their structure. Strong bases have either the OH or the ion as part of their structure. Soluble ionic oxides, such as K2O, are strong bases because the oxide ion is not stable in water and reacts immediately to form hydroxide ion ... 

The quantity of dissolved Mn(II) in natural waters depends on the solubility of hydroxide, carbonate and sulphide. In most natural waters the equilibrium concentration of dissolved manganese is determined by the MnC03 solubility. The production of Mn(OH)2 is considered only in a stronger alkaline medium. In the presence of hydrogen sulphide and its ionic forms the Mn(II) solubility in alkaline media is limited by the MnS solubility and the equilibrium concentrations are the lowest under these conditions. 

Bitea et al. [2003BIT/MUL] discuss the stability of thorium colloids generated by cou-lometric titration of 10 to 10 M thorium solutions at pH 3 - 5 in 0.5 M NaCl. Using laser-induced breakdown detection (LIBD) and ultrafiltration the colloids formed above the solubility limit of Th(lV) hydroxide were found to be stable within the time period of investigation (up to more than 400 days). Dilution of colloid containing test solutions at constant pH leads to the degradation of colloids into soluble ionic species, whereas dilution with neutral 0.5 M NaCl results in increased over-saturation and colloid formation, as recognised by a pH shift to lower values. This observation was ascribed to the simplified reaction ... 

Another important class of strong electrolytes consists of the strong bases, soluble ionic compounds containing the hydroxide ion (OH ). When these compounds are dissolved in water, the cations and OH ions separate and move independently. Solutions containing bases have a bitter taste and a slippery feel. The most common basic solutions are those produced when solid sodium hydroxide (NaOH) or potassium hydroxide (KOH) is dissolved in water to produce ions, as follows (see Fig. 4.7) ... 

Differentiate between the formula equation, the complete ionic equation, and the net ionic equation. For each reaction in Question 6, write all three balanced equations. What is an acid-base reaction Strong bases are soluble ionic compounds that contain the hydroxide ion. List the strong bases. When a strong base reacts with an acid, what is aiways produced Expiain the terms titration, stoichiometric point, neutralization, and standardization. 

The solubility products of selected compounds are listed in Table 11.4. Solubility product expressions can be used only for sparingly soluble salts. They cannot be used (without modification) for very soluble salts (like sodium chloride) because the concentration of ions is so high that the ions influence each other and the effective concentration of ions is lower than their concentration in mol dm . The errors in using similar equations for slightly soluble ionic substances (such as calcium hydroxide) are smaller, but are still significant in accurate work. (Now try Exercise 1 IE.)... 

Example 11.2 considers a slightly different case, where the relevant ions are introduced by adding two very soluble ionic substances (iron(II) sulfate and sodium hydroxide) to water. 

To predict whether a precipitate forms when we mix aqueous solutions of two strong electrolytes, we must (1) note the ions present in the reactants, (2) consider the possible cation-anion combinations, and (3) use Table 4.1 to determine if any of these combinations is insoluble. For example, will a precipitate form when solutions of Mg(N03)2 and NaOH are mixed Both substances are soluble ionic compounds and strong electrolytes. Mixing the solutions first produces a solution containing Mg, N03, Na, and OH ions. Will either cation interact with either anion to form an insoluble compound Knowing from Table 4.1 that Mg(N03)2 and NaOH are both soluble in water, our only possibilities are Mg " with OH and Na with N03. From Table 4.1 we see that hydroxides are generally insoluble. Because Mg " " is not an exception, Mg(OH)2 is insoluble and thus forms a precipitate. NaN03, however, is soluble, so Na" " and NO3 remain in solution. The balanced equation for the precipitation reaction is... 

V TABLE 4.2 lists the strong acids and bases we are most likely to encounter. You need to commit this information to memory in order to correctly identify strong electrolytes and write net ionic equations. The brevity of this list tells us that most acids are weak. (For H2SO4, as we noted earlier, only the first proton completely ionizes.) The only common strong bases are the common soluble metal hydroxides. Most other metal hydroxides are insoluble in water. The most common weak base is NH3, which reacts with water to form OH ions (Equation 4.11). 

The most common soluble strong bases are the ionic hydroxides of the alkali metals, such as NaOH, KOH, and the ionic hydroxides heavier alkaline earth metals, such as Sr(OH)2. These compounds completely dissociate into ions in aqueous solution. Thus, a solution labeled 0.30 M NaOH consists of 0.30 MNa ([Pg.665]

---