[sm2345]

This is my question:

Arrange in increasing order of freezing point of 1N aq. solution of the following compounds:

sucrose, K2SO4, NaCl, Na3PO4

Well, my logic is this:

1N sucrose= 1M sucrose= 342gm sucrose in soln.

1N K2SO4= .5M K2SO4= 88 gm K2SO4 in soln.

1N NaCl= 1M NaCl= 58.5 gm NaCl in soln.

1N Na3PO4= 1/3 M Na3PO4 = 54.67 gm Na3PO4 in soln.

We know if mass of solute present ↑
 
                mass of solvent ↓ (As concentration is constant = 1N)

hence        Molality ↑

and        :delta:T_f  ↑ (as  :delta:T_f is proportional to molality)     

ie.           freezing point ↓

Thus arranging in incr. order of freezomg point,
 
 Sucrose<K2SO4<NaCl<Na3PO4

Is the answer and my logic correct?       

[Arkcon]

Review the definition if colligative properties.  It does not use molarity or grams, but something else.  Also, I hate your teacher, for using normality, for salts, without telling us if it is in respect to the anion or the cation.  I truly don't know where to begin comparing these salt solutions to each other.

[Borek]

My bet is that question asks about Van't Hoff factor, but I agree with Arkcon - stating 1N for each of these solutions without giving additional information is asking for corporal punishment.