A saturated solution of Na2SO4 with excess of the solid is present in equilibrium with its vapor in a closed vessel. Calculate the number of degrees of freedom, f, of the system. Ignore the autoprotolysis of water and assume that the salt solvates without ionizing.
F = c - p +2 or use f = c-p +2 -r -a
c = chem species
p = phases
r = independant chemical reactions
a = additional restrictions
Solution provides a calculation of the degrees of freedom, with the assumption that the salt solvates without ionizing.