Math relationship for b.pt.
elevation and f. pt depression
 Dtf = I mkf  kf is the freezing pt constant
i = no of particles in solution per formula unit
For molecular species i =1
For NaCl i =                 These i values
For K2SO4 i =                assume 100%
For Al2(SO4)3 i =           ionization.
For water kf = 1.86oC/m