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Calculate the mean ionic activity of a \(0.0350 \mathrm{m} \mathrm{Na}_{3} \mathrm{PO}_{4}\) solution for which the mean activity coefficient is 0.685

At \(25^{\circ} \mathrm{C},\) the equilibrium constant for the dissociation of acetic acid \(K_{a}\) is \(1.75 \times 10^{-5}\). Using the Debye-Hückel limiting law, calculate the degree of dissociation in \(0.150 \mathrm{m}\) and \(1.50 \mathrm{m}\) solutions using an iterative calculation until the answer is constant to within \(+/-2\) in the second decimal place. Compare these values with what you would obtain if the ionic interactions had been ignored. Compare your results with the degree of dissociation of the acid assuming \(\gamma_{\pm}=1\)

Estimate the degree of dissociation of a \(0.200 \mathrm{m}\) solution of nitrous acid \(\left(K_{a}=4.00 \times 10^{-4}\right)\) that is also \(0.500 \mathrm{m}\) in the strong electrolyte given in parts (a) through (c). Use the data tables to obtain \(\gamma_{\pm},\) as the electrolyte concentration is too high to use the Debye-Hückel limiting law. a. \(\mathrm{Ba}(\mathrm{Cl})_{2}\) b. \(\mathrm{KOH}\) \(\mathbf{c} . \mathrm{AgNO}_{3}\) Compare your results with the degree of dissociation of the acid in the absence of other electrolytes.

Calculate the ionic strength in a solution that is 0.0750 \(m\) in \(\mathrm{K}_{2} \mathrm{SO}_{4}, 0.0085 \mathrm{m}\) in \(\mathrm{Na}_{3} \mathrm{PO}_{4},\) and \(0.0150 \mathrm{m}\) in \(\mathrm{MgCl}_{2}\)

Calculate the solubility of \(\mathrm{CaCO}_{3}\left(K_{s p}=3.4 \times 10^{-9}\right)(\mathrm{a})\) in pure \(\mathrm{H}_{2} \mathrm{O}\) and \((\mathrm{b})\) in an aqueous solution with \(I=0.0250 \mathrm{mol} \mathrm{kg}^{-1} .\) For part \((\mathrm{a}), \mathrm{do}\) an iterative calculation of \(\gamma_{\pm}\) and the solubility until the answer is constant in the second decimal place. Do you need to repeat this procedure in part (b)?

Calculate the mean ionic molality and mean ionic activity of a \(0.105 \mathrm{m} \mathrm{K}_{3} \mathrm{PO}_{4}\) solution for which the mean ionic activity coefficient is 0.225

Calculate the value of \(m_{\pm}\) in \(5.5 \times 10^{-3}\) molal solutions of (a) \(\mathrm{KCl}\) (b) \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2},\) and (c) \(\mathrm{ZnSO}_{4}\). Assume complete dissociation.

Calculate the pH of a buffer solution that is 0.200 molal in \(\mathrm{CH}_{3} \mathrm{COOH}\) and 0.15 molal in \(\mathrm{CH}_{3} \mathrm{COONa}\) using the Davies equation to calculate \(\gamma_{\pm} .\) What pH value would you have calculated if you had assumed that \(\gamma_{\pm}=1 ?\)

Use the Davies equation to calculate \(\gamma_{\pm}\) for a 1.00 molar solution of KOH. Compare your answer with the value in Table 10.3