The secret is remembering a little emphasized point when these problems are worked. That point is---"the extent to which these thing happen depends SOLELY on the number of dissolved particles."
So how many particles do we get when NaCl dissolves.
NaCl ==> Na^+ + Cl^- = 2.
MgCl2 ==> Mg^+2 + 2Cl^- = 3
KClO3 ==> K^+ + ClO3^- = 2
CO2 ==> doesn't dissolve to an appreciable extent and what little dissolves doesn't produce many ions so let's call this zero.
MgSO4 ==> Mg^+2 + SO4^-2 = 2
So which one produces the largest number of particles (all of them are the same molality). That would be MgCl2.
Solutions are made that contain 0.1 moles of each of the following compounds below in 100 g of H2O. Choose the compound whose solution will have the lowest freezing point.
NaBr
MgCl2----
KClO3
CO2
MgSO4
I know the answer is MgCl2
but I don't know how to get it. I know I have to use a periodic table but don't see the solution please explain
1 answer
1 answer