Sodium chloride is a 2-ion electrolyte, dissociating 90% in a certain concentration. How to calculate (a) its dissociation actor and (b) the freezing point of a molal solution?

Answer 1

Hi Jensen B. again,

Definition of molality is # moles solute in 1 kg water (NOT, in 1 kg solution total). The freezing point depression constant for water, 1.86.deg.C/molal, assumes one dissolved particle per mole of solute. Since NaCl under the specified conditions makes 0.90*2 + 0.10*1 = 1.9 moles of ions/mole of salt, then a 1 molal solution will exhibit a freezing point depression of 1.86*1.9 .deg.C.

Not sure what a dissociation actor is. Maybe one who is evidently not investing any emotional energy into acting his/her role on stage? Or, perhaps, one who is not a member of the customary actors' equity association (a walk-on, or a scab).

-- Cheers, --Mr. d.