The Nature of Aqueous Solutions Strong and Weak Electrolytes

Structure of tbe alcohol molecules, which is shown in Fig. 4.3(a). The molecule contains a polar O—H bond like those in water, which makes it very compatible with water. The interaction of water with ethanol is represented in Fig. 4.3(b). 

Many snbstances do not dissolve in water. Pure water will not, for example, dissolve animal fat, because fat molecules are nonpolar and do not interact effectively with polar water molecules. In general, polar and ionic substances are expected to be more soluble in water than nonpolar substances. Like dissolves Uke is a useful rule for predicting solubility. We will explore the basis for this generalization when we discnss the details of solution formation in Chapter 11. 

What if no ionic solids were soluble in water How would this affect the way reactions 

An electrolyte is a substance that when dissolved in water produces a solution that can conduct electricity. 

The Nature of Aqueous Solutions Strong and Weak Electrolytes 

Recall that a solution is a homogeneous mixture. It is the same throughout (the first sip of a cup of coffee is the same as the last), but its composition can be varied by changing the amount of dissolved substances (one can make weak or strong coffee). In this section we will consider what happens when a substance, the solute, is dissolved in liquid water, the solvent. 

One useful property for characterizing a solution is its electrical conductivity, its ability to conduct an electric current. This characteristic can be checked conveniently by using an apparatus like the one shown in Fig. 4.4. If the solution in the container conducts electricity, the bulb lights. Some solutions conduct current very efficiently, and the bulb shines very brightly these solutions contain strong electrolytes. Other solutions conduct only a small current, and the bulb glows dimly these solutions contain weak electrolytes. Some solutions permit no current to flow, and the bulb remains unlit these solutions contain nonelectrolytes. 

The basis for the conductivity properties of solutions was first correctly identified by Svante Arrhenius, then a Swedish graduate student in physics, who carried out research on the nature of solutions at the University of Uppsala in the early 1880s. Arrhenius came to believe that the conductivity of solutions arose from the presence of ions, an idea that was at first scorned by the majority of the scientific establishment. However, in the late 1890s when atoms were found to contain charged particles, the ionic theory suddenly made sense and became widely accepted. 

As Arrhenius postulated, the extent to which a solution can conduct an electric current depends directly on the number of ions present. Some materials, such as sodium chloride, readily produce ions in aqueous solution and are thus strong electrolytes. Other substances, such as acetic acid, produce relatively few ions when dissolved in water and are weak electrolytes. A third class of materials, such as sugar, form virtually no ions when dissolved in water and are nonelectrolytes. 

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The Nature of Aqueous Solutions—Solutes in aqueous solution are characterized as nonelectrolytes, which do not produce ions, or electrolytes, which produce ions. Ionic compounds produce ions by dissociation whereas molecular compounds produce ions via ionization. Weak electrolytes ionize to a limited extent, and strong electrolytes dissociate or ionize almost completely into ions. In addition to the molarity based on the solute as a whole, a solution s concentration can be stated in terms of the molarities of the individual solute species present— molecules and ions. 

The authors aim was to produce a text which critically reviews the available literature on solution adsorption phenomena and offers an interpretation of the surface-related interactions of activated carbons that is consistent for the adsorption of a wide variety of solutes ranging from strong electrolytes to organic non-electrolytes. The seven chapters cover the activation of carbon, surface oxygen functional groups and neutralization of base by acidic surface oxides, spectroscopic methods for molecular structure determinations on surfaces, nature of the electrical double layer, adsorption of electrolytes, and adsorption of weak and non-electrolytes from aqueous solution. 

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