Question

Which of the following solutes will lower the freezing point of water the most?

A) the molecular compound sucrose (C12H22O11)

B) the iconic compound magnesium sulfate (MgSO4)

C)the iconic lithium chloride (LiCI)

D)the iconic compound calcium fluoride(CaF2)

Answer 1

The decrease of the freezing point is directly proportional to the active number of particles in the solution. You have to be familiar with the number of particles each of the compounds can form when dissolved in water. The more number of particles they form more the freezing point will decrease.

The question has a problem, it doesn't said how much of each compound is putted in how much of water. Whiteout that it is impossible to tell.

If we assume that all the compounds are at the same concentration then the compound that produce more particles will be the one to decrease the freezing point the most.