Completely ionized solution

Thus, for any specified value of (D /K6)jjgQ2> the corresponding values of (D /K6) for a large number of completely ionized solutes can be obtained from eq 20 using data on (-AAG/RT) for different ions available in the literature (, ). ... 

RPC separations of ionic samples usually require ionic additives to the mobile phase, which may cause problems in HPLC/MS operations. Completely ionized solutes are much less retained than the corresponding uncharged species and elute close to the column hold-up volume, often as asymmetric or even split peaks. Weak acids are eluted in order of decreasing constants and weak bases... 

Chemical Potentials and Standard States for Completely Ionized Solutions... 

Using the data on —AAG/R7 for Na and Cl ions for the membrane material-solution involved, the value of In Cj aci particular membrane can be calculated from the value of (0 m/Ct/ )NaCi specified for the membrane. Also, using the value of In so obtained, the corresponding value of AmXA/S for any completely ionized solutes can be obtained from the equation... 

Here, for completely ionized solutes we define the mole fraction for the ith positively charged species in solution by where the index j runs over aU distinct chemical compounds added... 

Solutions of dinitrogen pentoxide in nitric acid or sulphuric acid exhibit absorptions in the Raman spectrum at 1050 and 1400 cm with intensities proportional to the stoichiometric concentration of dinitrogen pentoxide, showing that in these media the ionization of dinitrogen pentoxide is complete. Concentrated solutions in water (mole fraction of NgOg > 0-5) show some ionization to nitrate and nitronium ion. Dinitrogen pentoxide is not ionized in solutions in carbon tetrachloride, chloroform or nitromethane. ... 

Hydrogen chloride is completely ionized in aqueous solutions at all but the highest concentrations. Thermodynamic functions have been deterrnined electrochemicaHy for equations 7 and 8. Values are given in Table 7. 

Bases, like acids, are classified as strong or weak. A strong base in water solution is completely ionized to OH- ions and cations. As you can see from Table 4.1, the strong bases are the hydroxides of the Group 1 and Group 2 metals. These are typical ionic solids, completely ionized both in the solid state and in water solution. The equations written to represent the processes by which NaOH and Ca(OH)2 dissolve in water are... 

As we have pointed out, strong acids and bases are completely ionized in water. As a result, compounds such as HC1 and NaOH are strong electrolytes like NaCl. In contrast, molecular weak acids and weak bases are poor conductors because their water solutions contain relatively few ions. Hydrofluoric acid and ammonia are commonly described as weak electrolytes. 

He proposed that salts, strong acids, and strong bases are completely ionized in dilute water solution. Today, it seems quite reasonable that solutions of NaCI, HCI, and NaOH contain, respectively, Na+ and Cl- ions, H+ and Cl- ions, and Na+ and OH- ions. It did not seem nearly so obvious to the chemistry faculty at Uppsala in 1884. Arrhenius s dissertation received the lowest passing grade "approved not without praise."... 

The fact that strong acids and bases are completely ionized in water makes it relatively easy to calculate the pH and pOH of their solutions (Example 13.3). 

Nitric acid is a strong acid, completely ionized to H+ and N03 ions in dilute water solution HN03(flq)---------------------------- H+(aq) + N03( q)... 

Sulfuric acid is a strong acid, completely ionized to H+ and HS04 ions in dilute water solution. The HS04 ion, in contrast, is only partially ionized. 

Strong base A species that is completely ionized to OH- ions in dilute water solution, 81... 

Strong electrolyte A compound that is completely ionized to ions in dilute water solution, 37 Strontium, 543 Strontium chromate, 434 Structural formula A formula showing the arrangement of bonded atoms in a molecule, 34,579-580,586,590,593, 597... 

Of course, in aqueous solution the reactants and the products exist wholly or partly in their ionized forms the acid, nitrite, and salt exist as H+X , Na+N02, and Na+X , while the diazonium salts are practically completely ionized and the amine is in equilibrium with the corresponding ammonium ion, Ar—NH3. The question of which of these various species are involved in the substitution proper will be dealt with in Chapter 3. Although it is generally desirable to introduce ionized forms into equations, this is inappropriate for the overall equation for the diazotization process, as will become apparent in the discussion of the reaction mechanism (Ch. 3) and from the following remarks. 

Were kinetics experiments carried out with HI as the source of I- and H+ ions, the rate would be proportional to the square of the analytical (formal) concentration, Chi-That is, the product [I ][H+] is equal to Chi2, since HI is a very strong acid in aqueous solution. Yet, were one to take this observation literally, not remembering the complete ionization of HI, the application of Rule 1 would have suggested a transition state containing the elements of two molecules of HI, not one. 

Extractive alkylation is used to derivatize acids, phenols, alcohols or amides in aqueous solution [435,441,448,502]. The pH of the aqueous phase is adjusted to ensure complete ionization of the acidic substance which is then extracted as an ion pair with a tetraalkylammonium hydroxide into a suitable immiscible organic solvent. In the poorly solvating organic medium, the substrate anion possesses high reactivity and the nucleophilic displacement reaction with an alkyl halide occurs under favorable conditions. 

It has already been pointed out that weak electrolytes do not ionize to a sufficient extent in solution, and are far from being completely ionized even at very great dilution. The practical determination of A0 in such cases is, therefore, not possible but it can be calculated with the help of Kohlrausch s law. From the relationship, A+/A0 = N, one can straightaway write... 

For example, a buffering solution can be made from ethanoic acid (CH3COOH) and its salt sodium ethanoate (CH3COONa). Sodium ethanoate completely ionizes in water to form sodium ions and ethanoate ions ... 

As already mentioned, the criterion of complete ionization is the fulfilment of the Kohlrausch and Onsager equations (2.4.15) and (2.4.26) stating that the molar conductivity of the solution has to decrease linearly with the square root of its concentration. However, these relationships are valid at moderate concentrations only. At high concentrations, distinct deviations are observed which can partly be ascribed to non-bonding electrostatic and other interaction of more complicated nature (cf. p. 38) and partly to ionic bond formation between ions of opposite charge, i.e. to ion association (ion-pair formation). The separation of these two effects is indeed rather difficult. 

Strong acids (those that ionize completely in solution) are more likely to dissolve solids because charged particles such as hydrogen ions will interact more strongly with solids than will neutral particles. Weak acids do not readily donate hydrogen ions and consequently remain mostly in the neutral form. As a result, weak acids do not dissolve solids as readily as strong acids. 

Note in dilute solution, H2S04 is completely ionized and is considered to be a strong diprotic acid. 

---