Every year, oral rehydration therapy (ORT)-the feeding of an electrolyte
solution-saves the lives of countless children worldwide who become severely
dehydrated as a result of diarrhea. One requirement of the solution used is
that it be isotonic with human blood.(a) One definition of an isotonic
solution given in the text is that it have the same osmotic pressure as \(0.92
\% \mathrm{NaCl}(\mathrm{aq})\) (mass/volume). Another definition is that the
solution have a freezing point of \(-0.52^{\circ} \mathrm{C}\) Show that these
two definitions are in reasonably close agreement given that we are using
solution concentrations rather than activities.(b) Use the freezing-point
definition from part (a) to show that an ORT solution containing \(3.5
\mathrm{g} \mathrm{NaCl}\) \(1.5 \mathrm{g} \mathrm{KCl}, 2.9 \mathrm{g}
\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}\) (sodium
citrate), and \(20.0 \mathrm{g} \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\)
(glucose) per liter meets the requirement of being isotonic. [Hint: Which of
the solutes are nonelectrolytes, and which are strong electrolytes?]