Sodium hydroxide solution species calculation

Use the heat of solution data in Table B.IO and solution heat capacity data to (a) calculate the enthalpy of a hydrochloric acid, sulfuric acid, or sodium hydroxide solution of a known composition (solute mole fraction) relative to the pure solute and water at 25 C (b) calculate the required rate of heat transfer to or from a process in which an aqueous solution of HCl, H2SO4, or NaOH is formed, diluted, or combined with another solution of the same species and (c) calculate the final temperature if an aqueous solution of HCl, H2SO4, or NaOH is formed, diluted, or combined with another solution of the same species adiabatically. Perform material and energy balance calculations for a process that involves solutions for which enthalpy-concentration charts are available. 

Example 8.10 shows how the pH is calculated at the first equivalence point of the titration of phosphoric acid with sodium hydroxide, where the solution contains H2PO4-. Note that the pH of the solution does not depend on the concentration of H2P04 in the solution. Thus the pH is 4.67 at the first equivalence point in any typical titration of H3PO4. Likewise, at the second equivalence point, where the major species are HP042 and H20, the pH is calculated from the expression... 

The role of adsorption in the electroreduction of aromatic nitrocompounds has been studied by several electrochemical techniques. Kastening et a/. (290 291) calculated adsorption coefficients for p-chloronitrobenzene in various aqueous methanolic solutions of sodium hydroxide and in the presence of several concentrations of an inhibitor. From these studies, it was concluded that electron transfer occurred to an adsorbed species but that subsequent reactions of the anion radical may take place in the boundary layer ... 

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